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Journal of The Lepidopterists1 Society
Volume 14 1960 Number 4
THE DISTRIBUTION, HABITS, AND LIFE HISTORY OF EUPTYCHIA MITCHELLII (SATYRID^)
by Wilbur S. McAlpine, Stephen P. Hubbell, and Thomas E. Pliske1
Mitchell's Satyr, Euptychia mitchellii French (figs.19,20), is an inconspicuous brownish butterfly of the family Satyridae. It is seldom seen in collections, for it lives in secluded places and is very local in distribution. Its habitat, from which it never strays more than a few feet, is a type of bog characterized by Tamarack (Larix laricina) and Poison Sumac {Rhus vern-ix). The range of this butterfly is small; the species is known from only fifteen localities, nine of which are in southern Michigan. Doubtless because of its restricted occurrence and the rather inaccessible and inhospitable environment in which it lives, E. mitchellii is one of the few satyrids of the eastern United States for which no description of the life history has been published. The studies here reported were undertaken to fill this gap.
The closest relatives of Euptychia mitchellii are E. a. areolata J. E. Smith and its northern subspecies E. a. septentrionalis Davis, and E. cymela Cramer. The latter, which is common in the territory inhabited by mitchellii and sometimes occurs with it, is easily distinguished by the well-marked ocelli on the UDper surface of its wings, its lighter coloration, and its stronger flight. In Michigan cymela generally flies from early June until the middle of July, in contrast with the brief flight period of mitchellii; its time of occurrence varies greatly, however, depending upon conditions in different seasons.
1More than twenty years ago the senior author reared Euptychia mitchellii from egg to adult; he photographed, drew and described the immature stages, and in 1939 presented his results in a talk before the Detroit Entomological Society. His findings were not, however, published, and the two junior authors, not knowing of the earlier work, made an independent study of the lifc history of this butterfly in 1958. Subsequent comparison of notes led to collaboration on the present paper, which summarizes all that is known concerning the occurrence and life history of the species. The field observations and detailed descriptions of the immature stages are by McAlpine and Hubbell, the rearing data by McAlpine and Pliske, the photographs by McAlpine, and the line drawings by Hubbell.
The authors acknowledge with gratitude the help of various sorts given them by Drs. T. H. Hubbell, Warren H. Wagner, Jr., and Edward G. Voss, all of the University of Michigan, in connection with this study.
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210 McAlpine, Hubbell, Pliske: Euptychia Vol.14: no.4
The relationship of E. mitchellii to E. areolata is evidently much closer than to cymela. The two agree in being dark-colored and in lacking ocelli on the upper surfaces of the wings (though in some specimens of mitchellii, especially females, the ocelli of the lower surface show through faintly). The differences between typical areolata and mitchellii in the markings of the under surface are, however, striking. In E. a. areolata ocelli are absent or very small and indistinct on the fore wings, while those of the hind wings are elongate and narrow; in mitchellii the ocelli of the fore wings are always present and usually well defined, and those of the hind wings are slightly oval to nearly circular. Euptychia a. areolata occurs from Texas to Florida and Georgia; northward along the Atlantic coastal plain it intergrades clinally with the northern subspecies, E. a. septentrionalis, the type locality of which is Lakehurst, New Jersey. Subspecies septentrionalis is distinctly more like mitchellii in appearance; although the lower surface of the fore wings is (almost without ocelli, the ocelli of the hind wings are shorter and more oval than in typical areolata, longer and narrower than in mitchellii. It is possible that the isolated New Jersey records of mitchellii discussed below might have been based on specimens of E. a. septentrionalis showing extreme variation in the direction of mitchellii, or even, as has been suggested to the authors by T. H. Hubbell and W. H. Wagner, Jr., that mitchellii is a well defined subspecies of areolata. In the absence of proven intergradation, however, mitchellii should be regarded as a species distinct from areolata.
History and Distribution
Mitchell's Satyr was described as Neonympha Mitchellii by G. R. French (1889 : 25) from six males and four females taken by Prof. J. N. Mitchell at Wakelee in Cass County, Michigan, in "a dry upland meadow near a wet meadow and marsh." Later Mitchell found the species much more abundant in the marshy area. R. H. Wolcott (1893 : 102) reported mitchellii from a two acre bog in South Grand Rapids, Kent County, Michigan, noting that he had collected it there some three years before French described it and had found the species common in the same place each year from 1886 to 1893. Wolcott's bog has been destroyed by the growth of Grand Rapids, but some of his specimens still exist; two, taken July 20, 1892, and July 7, 1893, are in the University of Michigan Museum of Zoology. Mitchell apparently knew of Wolcott's discovery, since in discussing mitchellii French (1889 : 27) remarked, "Professor Mitchell is of the opinion that the species has been found as far north as Kent County, Michigan."
S. H. Scudder (1889 : 1785) redescribed Neonympha mitchellii in minute detail, apparently from specimens sent him by French. Maynard (1891 : 218) included the species in his Manual, and it was listed in Skinner's Catalogue (1898), but no additional records were published until Holland, in The Butterfly Book (1898 : 203) reported it from "northern
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New Jersey, near Lake Hopatcong," and J. B. Smith, in the Insects of New Jersey (1900: 373; 1910: 413) noted its capture by C. W. Johnson at Dover in June. Pallister (1927 : 203) also refers to a specimen taken at Dover by Johnson, but gives the date as July 10, 1890. Englehardt (1936: 110, 221) thought that the Lake Hopatcong and Dover records might have been based on the same specimens, the location of which was not known to him; but McAlpine saw a male and female E. mitchellii in the collection of Frank Chermock of Pittsburg, labelled as taken at Wood-port on Lake Hopatcong but without date or collector's name, which were probably the basis of Holland's record. In 1938 C. F. dos Passos (in litt.) informed McAlpine that a careful search made that year for mitchellii in likely spots near Lake Hopatcong had been unsuccessful. In more recent attempts A. B. Klots also failed to find it, and noted that much of the boggy land around the lake where it might have been expected to occur has been filled in for residential purposes; he is of the opinion (1951 : 66) that the northern New Jersey records (Dover and Woodport) "are a bit dubious."
J. C. Pallister (1927: 203) reported that he had found E. mitchellii in a swampy meadow on the edge of a peat swamp near Streetsboro in Portage County, Ohio, where it was "very abundant" on July 4, 1925, and "plentiful" on July 10, 1926. This new locality was included by Holland in the second edition of The Butterfly Book (1931 : 180). George Rawson, writing about mitchellii to E. G. Voss in 1954, said that some 15 years earlier he, with E. S. Thomas and John Thomas, went to Streetsboro to look for the species, but without success, the bog having been converted into a truck farm. Edward C. Welling, however, in a letter to Voss, mentions a specimen taken in "the Streetsboro bogs" on June 10, 1950.
McAlpine first encountered E. mitchellii in 1934, at the type locality near Wakelee in Cass County, Michigan; he continued his observations of the colony there at intervals until 1940, accompanied on some occasions by Sherman Moore and W. W. Newcomb. In brief notes (1936: 110, 221) he reported that at Wakelee the species "is found along very narrow grassy strips bordering small watercourses in the middle of a dense tamarack swamp," and mentioned that he had obtained eggs and was carrying a number of larvae over the winter. Sherman Moore (1939: 8) listed the species from two new localities, Kalamazoo and Washtenaw counties, Michigan. The first of these records was based on three males (the only individuals seen) collected by McAlpine on July 11, 1937, along a small stream in a tamarack bog at Sugar Loaf Lake in southern Kalamazoo County. Specimens from that county, taken July 7 and 14, are also in the collection of Michigan State University, according to R. W. Hodges. Moore's Washtenaw County record was based on specimens taken in various years from a colony in a small bog at Sharon Hollow, in Sharon Township, south of the present Waterloo Recreation Area, by George Rawson (discoverer of the colony), J. H. Newman, and Sherman Moore. In 1953 mitchellii was again collected
212 McAlpine,, Hubbell, Pliske: Euptychia Vol.14: no.4-
at the Sharon Hollow bog by Warren H. Wagner, Jr., who in 1957 took Hubbell and Pliske there and thus made possible their study. Another Washtenaw County locality, hitherto unrecorded, is near Willis, adjacent to the Wayne County line. Here Walter Stinson found a single male on July 10, 1931, in a tamarack swamp that had been cut over long ago, and McAlpine took another the following year, also on July 10. These were the only individuals found, in spite of careful search.
Recently a number of additional localities for E. mitchellii have come to light. Ronald Hodges (in litt.) mentions a specimen from Barry County, Michigan, taken on July 24, as being in the Michigan State University collection. In 1955 M. C. Nielsen found a colony in a bog in the Three Rivers State Game Reserve in St. Joseph County, Michigan, (Section 7, T.7 S., R.12 W.) ; specimens have been taken there on July 4, 6, and 8. In 1958 E. G. Voss located a colony in another bog on the same Reserve, but in Cass County. The same year Voss found E. mitchellii common on July 16 in a boggy area about one mile west of Millburg in Benton Township, Berrien County, Michigan; here it occurred in an open area of sedges and grasses in a swamp forest of Tamarack, Poison Sumac, and White Birch, near Blue Creek. All of the known Michigan county records are included in Moore's revised list of Michigan butterflies (1960).
George Rawson, in the letter mentioned above, states that in 1954 Donald Eff of Boulder, Colorado, received two specimens taken by an Indiana collector at Cedar Lake, about 15 miles south of Hammond, in Lake County, Indiana. Finally, F. S. Badger (1958 : 41) has recently described the results of his search for E. mitchellii. In Michigan he found it at the original Wakelee bog site, and also at the Three Rivers locality discovered by Nielsen. In Indiana he encountered it at Cedar Lake in LaGrange County, and one mile southeast of Fremont in Steuben County. This completes the list of known localities for the species; but with a knowledge of its habitat and food plants it should not be too difficult to find others.
Habitat and Behavior of Adults
The observations recorded here were made on two colonies of Euptychia mitchellii, the first set by McAlpine at the Wakelee bog (principally during the years 1935-1937), the other by Hubbell and Pliske at the Sharon Hollow bog in 1958.
The Wakelee bog, situated about one mile northeast of the town of Wakelee, lies in an elongate depression surrounded, except on the east and northeast, by rolling gravelly hills and upland. McAlpine estimated the area of the whole tract at more than 200 acres, of which considerably less than half is bog and marsh occupied by mitchellii, while Badger (1958 : 41) states that the bog is about a mile long and varies from one-quarter to one-half mile in width. The bounding slopes on the north and south rise fifty to seventy-five feet above the floor of the swamp and are covered with an
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open forest of hard maple, beech, oak, and hickory. On the west the swamp is bordered by an extensive upland meadow and an abandoned apple orchard. Along much of the bog margin are seepage areas and numerous springs on the adjoining slopes. The depression is drained to the east by a small creek called the Rocky River, fed by the wandering streamlets that cross the swamp. A mixed growth of Tamarack and Poison Sumac occupies the greater part of the bog, interspersed with Red Osier (Cornus stolonifera) and other shrubs; along the stream channels that cut through the forest are narrow belts of sedge marsh with occasional cattails and an abundance of water cress. The many small openings and a larger area of swampy meadow toward the east end have a ground cover made up principally of narrow-leaved sedges and marsh grasses. In 1935-1937 these marshy areas were pastured by cattle and more or less trampled; the sedges and grasses in them were not very tall, only one or two feet in height. Badger speaks of the "waist-high" growth in the sedgy areas at the time of his visit in 1954-1956, but this doubtless refers only to the open marsh. In the '30's most of the larger Tamaracks were dead, and growing up among them was a rather dense stand of young Tamaracks, tall Poison Sumac, and other shrubbery. To judge from Badger's description, the original density and height of the swamp forest have been regained in the succeeding twenty years.
During the years when this bog was visited by McAlpine (1934-1940) adults of Euptychia mitchellii were present from about July 1 to 15. The butterflies were closely restricted to the bog. They occurred both in the open meadow-like areas and along the narrow waterways through the stands of Tamarack, as well as at the margins of the swamp, and were generally found where sedges and grasses form the ground cover. Although mitchellii was quite abundant during its brief flight period, McAlpine believes that it would be most difficult to determine the mitchellii population in this bog with any degree of accuracy due to the rough terrain along the waterways, the uncertainty as to the size of the occupied areas and the variations in density of the butterflies from one part to another. McAlpine's observations do show that the population fluctuates noticeably in numbers from season to season.
McAlpine noted that the flight of E. mitchellii is weak and short, and usually just above the marsh grass; when a specimen is flushed by walking through the grass it usually flies only a short distance before alighting on a grass or sedge stem. Late in the afternoon he often found individuals hanging from the stems, where they were easy to capture. In collecting this butterfly great care must be taken, as the wing scaling is very easily rubbed off; unless specimens are caught soon after emergence they are always worn. An occasional Lethe eurydice Joh. was seen in the bog with mitchellii, and E. cymela occurred near the hardwood borders.
The observations made by Hubbell and Pliske at Sharon Hollow were begun in the summer of 1958. This bog is very much smaller than the one at Wakelee, with an area of only two or three acres, but is otherwise quite similar both in vegetation and surroundings. It occupies a hollow, bor-
214 McAlpine, Hubbell, Pliske: Euptychia Vol.14: no.4
dered on the south by an extensive, mature beech-maple forest, apparently virgin, which is equalled in grandeur by few others in southern Michigan. To the west lies a sloping, long-uncultivated field now being overgrown by willows, sumac, elms, and poplars; beyond is a small shallow body of water called Grass Lake. A small creek which drains this lake is bordered by large willows to the point where it enters the bog; thence it winds eastward, dividing the bog into two quite different parts. The southern section contains all the Tamarack and most of the Poison Sumac, with some Red Osier, and is much the larger in area. The northern section consists in part of a wet meadow occupied chiefly by sedges and grasses, in part of a boggy meadow where Shrubby Cinquefoil {Potentilla fruticosa) is dominant. To the north of these moist meadows are pastures on large hills, and to the east lowland pastures and cultivated fields.
On September 6, 1958, Edward G. Voss visited the bog and identified the woody plants present; his list is given here, since it helps to characterize the particular type of bog to which this butterfly is apparently confined.
Co-dominants: Larix laricina (Tamarack) and Rhus vernix (Poison Sumac). Other species: Acer rubrum, Aronia prunifolia, Betula lutea, B. pumila, Cornus obliqua, C. racemosa, C. stolonifera, Euonymus obovata, Fraxinus americana, F. nigra, Ilex verticillata, Juniperus communis (one), Lindera benzoin, Lonicera dioica, Parthenocissus quinquefolia, Populus del-toides, P. tremuloides, Potentilla fruticosa, Rhamnus alnifolia, Rhus glabra var. borealis, R. radicans, Ribes americana, R. hirtellum, Rosa palustris, Rubus pubescens, R. strigosus, Salix bebbiana, S. Candida, S. discolor, S. fragilis (one large), S. serisissima, Sambucus canadensis, Smilax tamnoides var. hisida, Tilia americana (one small), Vaccinium corymbosum, V. mac-rocarpon, TJlmus sp., and Vitis sp.
In addition to the above, more than 100 species of herbaceous plants were observed, including Sundews (Drosera) and Pitcher Plants (Sarracenia) in the wetter areas; relatively little sphagnum moss is present.
The first visit to the bog in 1958 was on July 5; the skies were overcast, and a light rain was falling when the bog was reached at 11:30 a.m. During the twenty minutes the rain continued, no E. mitchellii and few butterflies of any kind were seen. In the afternoon periods of rain alternated with brief intervals of sunshine, during which the year's first individuals of mitchellii were seen flying about. No females were found; of the four males followed and watched closely, none seemed selective of the objects upon which they rested. During the intermittent showers they sat with folded wings in some sheltered place, in a vertical position with head either up or down. In flight E. mitchellii could be easily distinguished from the other and more common satyr, E. cymela, which, although not a resident of the bog, often strayed into it. Euptychia mitchellii, as Badger has described, has a slow, weak flight, never rising more than a foot above the grasses and sedges even when disturbed. Seen from a distance, the flying insect appears and disappears among the grass tops, giving the effect of dancing and bobbing. Euptychia cymela, on the other hand, is a rather strong and jerky flier. It frequent-
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ly rises to fly in a zig-zag manner high about the foliage of a tree, where it often alights to sun itself; then suddenly it will drop to the level of the grass tops, where it will remain for some time.
A second trip to the bog was made on July 8. The weather was perfect, with sunny, clear skies. In the three day interval since the first visit E. mitchellii had increased tremendously in numbers; counts made in representative areas led to an estimate that 500 or more individuals were flying on this date, which was near if not at the peak of the flight period. The butterflies were quite evenly dispersed throughout the bog; as many were seen in the denser groves of Tamarack south of the creek as in the open meadows on the north side. In the boggy meadows individuals were easy to follow, but inevitably they seemed to move into an impenetrable stand of Poison Sumac or a wall of Tamarack trees, so that it was seldom possible to watch any single one for more than a quarter of an hour. During the late morning and afternoon 14 individuals of E. mitchellii were captured, examined to determine their sex, and released to be followed and watched. They did not seem to be much disturbed by this handling, since upon release they did not fly rapidly and wildly off. The first 13 examined were males in fresh condition; late in the afternoon a single female was found.
Many other species were flying in the bog and in the adjacent wet meadows on this same day, several of which were more numerous than E. mitchelli. Poanes massasoit Scudder was bv far the most abundant skipper. Atrytone conspicua Edw. was common in the northern and eastern peripheries of the bog, along with an occasional individual of A. logan Edw. Among the grasses and sedges of the northernmost meadow Lethe eurydice was flying with Euptychia mitchellii. (Both McAlpine and Hubbell observed that these two species are easily distinguished in flight; the first is more active, and its light brown color does not resemble the rich mahogany brown of E. mitchellii). Several specimens of Euphydryas phaeton Drury were collected and one or two battered individuals of Limenitis astyanax Fab. were seen within the bog. In the small, sheltered clearings Lyctena dorcas Kirby was found often, Boloria selene Schiff. frequently, and Strymon acadica Edw. and S. titus Fab, occasionally. Other visitors to the bog included Speyeria aphrodite Fab., S. cybele Fab., Boloria toddi Holland, Everes comyntas Godart, Colias philo-dice Latr., C. eurytheme Bdv., Pieris protodice Bdv. & Lee, P. napi Linne and Atrytone ruricola Bdv. Speyeria aphrodite and S. cybele congregated in large numbers in the meadow of Shrubby Cinquefoil, from which they strayed into the tamarack section of the bog. In the cinquefoil meadow occurred the largest colony of Lycana dorcas the junior authors have ever seen, containing perhaps several thousand individuals. Boloria toddi and B. selene were also abundant in this meadow, and an aberrant dark form of the first was captured here. Several Colias philodice and Ancyloxipha numitor Fab. were observed in the meadow, and two Speyeria idalia Drury and one very ragged survivor of Lyctena thoe Guerin were collected. Pieris napi strayed into the bog from the beech-maple woods on the south, and P. protodice came in at the southwest corner from the nearby open hillsides where it was common. Ad-
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ditional July records from the vicinity include Strymon liparops Bdv. & Lee, S. falacer Godart, Poanes viator Edw., Polites verna Edw., P. themis-tocles Latr., P. peckius Kirby, P. manataaqua Scudder, and Epargyreus clarus Cramer.
As noted above, the first female Euptychia mitchellii was found late in the afternoon, and from that time on, all attention was focused on her activities. During the more than an hour that she was watched she flew very little; her abdomen was swollen with a heavy burden of eggs, and when she did fly it was in short "jumps" of less than two feet. More often than not she alighted upon a sedge later identified as Carex stricta, but laid no eggs upon it. As evening approached she stopped flying altogether, and was evidently going to rest for the night. It therefore seemed best, in case females were actually as scarce as they seemed to be, to capture her alive in the hope that she would oviposit in confinement. This butterfly, taken to Ann Arbor in a tin container, was caged with samples of the common grasses and sedges of the bog, and laid the eggs which were reared by Pliske.
When the third visit was made, on July 11, the sky was partly cloudy all day, affecting the flight behavior of E. mitchellii. It seemed that whenever the sun passed behind a cloud, individuals that were flying would alight almost immediately; as soon as the sun reappeared they would begin to fly again. To test this impression several were watched at the same time in the wet meadow. Within moments after the sun was hidden every one had dropped out of sight into the grass; five minutes later, with the return of full sunshine, they were all on the wing again. During long periods of cloudiness without rain, however, some would fly. McAlpine had earlier observed that E. mitchellii, like other satyrids, can often be seen in flight on cloudy days. Although the objective of the trip had been to observe oviposition on the food plant, no females were found among many individuals examined. The males were still common, but their wings were becoming ragged and worn.
At the time of the next visit, July 16, the population of Euptychia mitchellii was found greatly reduced and all the males were battered. A fresh female was found in the meadow, and was kept under observation while a search was made for others. Five ragged males were caught, and then a second female, also fresh. Although closely watched for some time, neither female was seen to oviposit, and both were eventually lost in the denser parts of the bog. Fortunately, the female captured July 8 had in the meantime laid 107 eggs, many of which proved to be fertile.
From the observations made on E. mitchellii at Sharon Hollow it seems probable that the peaks of the flight periods of males and females are staggered, the females emerging later than the males. It also appears that in this locality the ratio of males to females may be as high as ten to one.
Subsequent trips to the Sharon Hollow bog were made on July 24, September 6, and October 3, primarily to map and describe the area and attempt to find the larvae in their natural habitat. No adults of E. mitchellii were seen on these occasions, and no eggs or larvae were found.
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Life History
The major features of the life history of Euptychia mitchellii may be summarized as follows: The species is single-brooded. In southern Michigan the flight season is restricted to about two weeks, generally about the first to the fifteenth of July, but varying somewhat with the season. The earliest dates for adults are June 21 (empty pupal case) and June 28 (capture), the latest July 20 (capture). Peak abundance of males is reached about July 4-8, and of females apparently a few days later. Oviposition occurs over a period of about ten days, an individual female laying as many as 10Q+ eggs on the stems of sedges. The eggs hatch in from seven to eleven days. Caterpillars reared in captivity rejected Car ex stricta, but reached maturity on two other species of Carex and one of Scirpus, suggesting that in their natural habitat they may eat various species of sedge. Three larval molts occur in the summer and fall, the last in early September. The sluggish fourth instar larva eats relatively little and soon attaches itself, an inch or two above the ground, to a stem or lower leaf of its food plant; it spins a few strands of silk or a thin silk pad to which it clings. Stiff and dormant, it passes the winter in this position, protected only by the drooping leaves of the sedge and whatever snow cover there may be. With the advent of warm weather the caterpillars again become active, probably usually after the middle of May. There are two more larval molts in the spring, followed by the molt to the pupal stage, which occurs in June. Emergence of the adult takes place in about 10 to 15 days.
Although oviposition was not observed in the field, eggs were obtained from females confined with grasses and sedges from the bogs. On July 14, 1935, McAlpine caged three females at the Wakelee bog and took them to his home in Birmingham; one died in transit. The following morning two eggs were found on grass stems. One of the remaining females was killed by a small grass spider on July 16; the other became entangled in the netting of the cage and died on July 17. On the morning of July 18 it was found that 81 eggs had been laid on the stems of the smaller grasses and sedges, to which they were somewhat insecurely attached by a vitreous substance. Additional eggs were obtained from a caged female the following year, and some of the larvae that emerged from both lots were reared to maturity.
The female caught at Sharon Hollow on July 8, 1958, was caged by Pliske with leaves of the presumed food plant, Carex stricta, in a large gauze-topped glass jar, which was placed where it received three hours of morning sunlight and was in shade the rest of the day, simulating conditions prevalent in the bog. This female laid 15 eggs on July 9 between 12:15 and
3 p.m., 5 on July 10 between 10:45 and 11:45 a.m., 36 on July 11 between 10 a.m. and noon, 25 on July 12 between 10 a.m. and 1 p.m., 6 on July 13 between 10:30 a.m. and noon, 4 on July 14 between 11 a.m. and noon,
4 on July 15 between 11 a.m. and noon, and 2 on July 16 at 10 a.m. She died on July 17, after having laid a total of 107 eggs. The eggs were not laid consistently on the sedge leaves, but at random, singly or in small groups, on the
I
218 McAlpine, Hue-bell, Pliske: Euptychia Vol.14: no.4
glass, earth, and sedge. This may have been because no stems were available, since the females caged by McAlpine oviposited almost exclusively on stems. Most of the eggs were laid during the hours when the jar was in sunlight, and more than half of them on two successive days, July 11 and 12. Each egg was placed in a separate glass vial for rearing.
The eggs obtained by McAlpine hatched in seven to eight days. Those obtained by Pliske hatched on six successive days, July 19-24, the respective numbers being 2, 11, 10, 14, 6, and 4, making a total of 47, or 44% of those laid. In this batch of eggs an average of 10 days elapsed between oviposition and hatching.
The most striking feature characteristic of the first instar larvae is the disproportionately large, bilobate, almost black head, which under close examination can be seen to be a very dark violet brown. Soon after hatching the larva usually eats most of the egg shell. Those reared by McAlpine fed on the leaves of two quite different sedges from the bog, entire plants of which were brought in and potted: Foxtail Sedge (Carex alopecoidea), which they appeared to prefer, and the "Bulrush" (Scirpus atrovirens). They would eat the tender tip, or start at the edge of the leaf and work to the center, and then eat downward, sometimes causing the leaf to bend over and droop. The larvae in Pliske's vials did not accept the leaves of the rather coarse sedge Carex stricta, but when offered a choice of eight kinds of grasses and sedges collected in the bog and about the house they fed with apparent avidity on Carex cephalophora and some were reared to maturity on it. Since this sedge grows in dry oak woods it can scarcely be one of the normal food plants. Probably E. mitchellii feeds on a variety of sedges; in any event the restricted occurrence of the butterfly is obviously not attributable to its choice of food. In McAlpine's rearings the duration of the first stadium was 12 to 14 days for most individuals and up to 18 days for a few; the average in Pliske's rearings was 16 days.
In Pliske's rearings the earliest Instar II larva appeared August 1, and by August 8 all forty of the healthy larvae had molted and entered this stadium, which had an average duration of 12 days. McAlpine's Instar II larvae molted at the end of 14 to 16 days.
The third and succeeding instars are quite similar in general appearance except for their increasing size - lime green with paler longitudinal lines, tapering to a somewhat constricted neck and bifurcate tail. The body surface is rather smooth in appearance to the unaided eye, but densely papillose and bristly as seen under a lens. In Pliske's vials the molt to the third instar occurred between August 13 and 18; in preparation for it the larvae took position, head up, on a mat of silk which each had spun 24 hours previous to the molt on the grass wall of the vial. The appetite of the Instar III larvae was noticeably smaller than in the previous stages, and the larvae were less active, spending much of each day motionless, and feeding only at intervals. McAlpine's third instar larvae rested head down on the underside of a sedge leaf near its base until late afternoon, when they did their feeding;
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those reared by Pliske more often fed in the morning. Since it appeared that this might be the stage in which hibernation would take place, Pliske placed about one-third of the vials containing third instar larvae outdoors, the rest being kept inside. The larvae outdoors remained inactive, did not feed, and molted between September 6 and 10, with an average duration of 26 days for the third stadium. Those kept indoors remained lethargic until the last two days of August, when they became more active and resumed eating; this group molted between September 4 and 9, with an average duration of 24 days for the third stadium. McAlpine's larvae, kept in an unheated garage, molted in early September after 16 to 20 davs in the 3rd stadium.
All of Pliske's larvae that had been put outdoors eventually died. Those kept indoors failed to enter diapause, which had begun to manifest itself as the lethargic interval in the third stadium, and proceeded with their development. They were fairly active and ate well, and all molted again between September 20 and 22, the average duration of the fourth stadium having been only 14 days. The fifth instar larvae continued to feed, but at a reduced rate, until shortly before pupation. On October 14 two of the remaining 15 healthy larvae attached themselves to a pad of silk on the sides of their vials, with the head down and curled underneath the body. One of these pupated the next day, and 10 others had done so by October 26, the average duration of the fifth stadium having been 30 days. Two larvae that had assumed the prepupational position were placed outdoors; they never completed pupation. About 12 days after pupation the bluish-green of the chrysalis began to acquire a brownish tinge, first in the area of the wings and later spreading to the whole surface. The change from green to brown was completed in an average of four days, and one day later the butterfly emerged, if at all. The insects that completed transformation were all males; the first emerged October 31, and four others by November 12. Six of the eleven pupae failed to transform.
Not knowing of McAlpine's prior findings, Hubbell and Pliske concluded that under natural conditions the winter would be passed as a fourth instar hibernating larva, and that a fifth and sixth instar would be expected to occur in the spring. This is suggested by the duration of the stadia in Pliske's rearings: I - 16 days; II - 12 days; III - 24-26 days; IV -14 days; V - 30 days. In this series the third and fifth stadia are much longer than the others. The length of the third is probably a normal feature of the life history (in McAlpine's rearings it was 16 to 20 days), reflecting the increasing sluggishness of the larvae with its approach to the diapause period. The long fifth stadium in the individuals that went uninterruptedly through their life history indoors was thought to correspond to two normal stadia. This conclusion was supported by the small size of the five reared males (wing expanse in mm. 25.8 - 30.0, mean 28.0) as compared with that of wild males taken at Sharon Hollow (wing expanse in mm. 31.6 - 34.8, mean 33.2), McAlpine's earlier rearings fully substantiate this hypothesis.
McAlpine in 1935 kept 13 hibernating caterpillars on potted sedges in his garage until late fall, when seven were placed outside in a bushel basket
220 McAlpine, Hubbell, Pliske: Euptychia Vol.14: no.4
set flush with the ground surface. A thaw in late February flooded the basket. Examination on March 22 revealed only two living larvae, one still clinging to its silken mat on <a dead sedge leaf, the other on the ground at the base of a sedge. They had been covered with water and ice during the last week in March and the first half of February and thus had survived a very severe test. One of these resumed activity, fed, and eventually pupated and emerged as a stunted male butterfly. In the summer of 1936, additional eggs were secured, and of the caterpillars that hatched three were carried through the winter and matured as full sized males. From these observations it appears that the fourth stadium normally endures from early September to late May of the following year, the fifth from 13 to 15 days, and the sixth from 12 to 15 days. The duration of the pupal stage McAlpine found to be from 10 to 15 days, while in the individuals reared indoors by Pliske it varied from 15 to 18 days.
McAlpine found two pupae in the Wakelee bog on June 21, 1936. One had already hatched (considerably earlier than usual) ; the other was photographed (figs. 17,18). They were both suspended by the cremaster from a button of silk attached to the underside of leaf blades of the sedge Scirpus atrovirens, within two or three inches of the ground,, as in the instance of those reared by McAlpine. They were about 15 mm. in length, a little larger than the pupae of the reared individuals.
Descriptions of the Immature Stages
The following descriptions were made by McAlpine and Hubbell from living and freshly killed specimens, which were then preserved in alcohol ; the descriptions were later verified and amplified by reference to preserved material. All of the precise color specifications are based on comparison with the plates in the Villalobos Colour Atlas (1947). For conciseness they are given as abbreviated formulae in which the hue is followed by degree of chromaticity and lightness value, thus lime, 5°-7°, 9-11.
EGG (figs. 11. 12). Spheroidal or rounded cubical, diameter 0.8-1.0 mm. Surface of shell covered with irregularly polygonal, shallow cells, usually 5- or 6- sided, each ±0.05 mm. across; cell margins very slightly raised, floors of enclosed saucer-like depressions finely and closely granular in appearance. Color whitish green to light lime green, changing to very pale brown before hatching; dark head of larva visible one or two days before hatching. Egg somewhat insecurely attached to stem of sedge by a vitreous substance. Duration of stage, 7-11 days.
FIRST INSTAR LARVA (figs. 1-4, 13). Body when newly hatched pale ochre or light yellow-green, including legs and prolegs; after feeding, light lime green; head with silky sheen, medium to dark violet brown verging on black, ocelli and mandibles dark brown.
Head very large and prominent, width and height 1.5 ± times that of body, length 0.67 zt times width. Vertex slightly angulate-impressed between right and left lobes of head, each lobe crowned with a rounded prominence bearing two coarse light brown pointed setae, one apical and erect, the other lateral and projecting anterolaterally. Side of head with several smaller protuberances, each topped with a single short, light brown seta: two above lateral ocelli, one slightly caudoventrad of the other; one just
1960 Journal of the Lepidopterists' Society 221
back of lateral ocelli; one, very small, a little ctarsocaudad of ventrolateral ocelli. Facial region with several short setae. Head surface densely and very shallowly pitted, resembling sand-blasted glass.
Body cylindrical, segments annulated, thoracic segments equal in height and breadth, except anterior part of prothorax slightly higher than broad. Caudal end large, dorsally with a pair of short, narrowly conical, slightly divaricate, backwardly directed processes separated by the large, rounded anal lobe, processes whitish or faintly rosy. Dorsal and lateral surfaces of body with many conspicuous light brown or colorless setae, clubbed or knobbed at tip, arising from low, conical but not papillose bases (fig. 4) ; these setae arranged as follows: prothorax with 10 on anterior part, 5 on each side of mid-dorsal line above spiracles and forming transverse row around body; me-sothorax and metathorax each with 8, 4 on each side of mid-dorsal line, arranged as on prothorax; abdominal segments 1-8 each with 10, 5 on each side of mid-dorsal line, of which 2 are dorsal, 1 lateral above spiracle, and 2 ventrolateral below spiracle on the fleshy substigmatal fold (which extends caudad from the mesothorax or metathorax, lying immediately above the bases of the prolegs and terminating above the base of the caudal proleg). Dorsal knobbed setae of first 8 abdominal segments arranged in two zigzag lines, one on each side of mid-dorsal line; lateral setae forming a straight line above spiracles; ventrolateral pair forming a zigzag line, with posterior seta of each segment slightly higher than anterior. Ninth abdominal segment with 4 knobbed setae, 2 on each side of mid-dorsal line; distolateral processes of terminal segment with a proximodorsal and a proximolateral seta in addition to one (rarely two) at the pointed tip. Admesal pair of knobbed setae of 9th abdominal segment longest, one-half length of head ; setas on dorsal head prominences, on dorsum of prothorax, and at tips of anal processes next in length; setae in dorsal zigzag rows somewhat shorter, the admesal ones longer than the outer ones. Ordinary pointed (unknobbed) setae arranged as follows: on prothorax a forked pair above leg base; on mesothorax and metathorax a single fine seta above each leg base; first and second abdominal segments each with 4 short ventral setae, 2 on each side of midventral line in transverse row; prolegs each with several fine, colorless setae, those of anal proleg 5, in close group on lateral surface; anal region with several minute, colorless setae and a forked pair just below each dorsolateral terminal process. Spiracles, except on prothorax and eighth abdominal segment, very small, inconspicuous; all ringed with pale brown.
Coloration: General body color light lime green (lime, 5°-7°, 9-11) ; longitudinal striping as follows: a pair of very faint white dorsal admesal lines inside the zigzag rows of setae, a broad dorsolateral whitish band, two very fine whitish stigmatal lines, and a broader whitish stripe on substigmatal fold.
Length at emergence, 2.5-3.0 mm; length at end of stadium, 4.5-6.0 mm. Duration of stadium 11-18 days.
SECOND INSTAR LARVA (fig. 5). Head and body light lime green, former with a trace of olive green. Head smaller in relation to body than in Instar I. Knobbed setae absent in this stage (and in all later stages), head and body covered irregularly and rather densely with small, fleshy, subconical whitish papillae, each abruptly apic-ulate, the seta-like tip being short, stout, blunt-ended, and colorless or light brown. Head bilobed as in Instar I, but crowning prominences less pronounced; each head-lobe topped with a low tubercle, light brown or faintly rosy, which in turn bears three minute papillae, the two more anterior ones larger than the third. Remainder of head with numerous papillae, surface between these densely and minutely pitted, the pitting slightly deeper than in Instar I. Body segments annulated except in immediate vicinity of spiracles; usually 5 or 6 annuli to the segment. Substigmatal fold forming a more prominent fleshy ridge than in Instar I. Caudal end of body bifurcate; the conical processes longer and basally broader, more pointed, and larger relative to anal lobe than in Instar I; their surfaces papillose like remainder of body, whitish, becoming light brown or faintly rosy at extreme tip.
Coloration: General color of head and body light lime green (lime, 5°-7°, 12-13) ; whitish striping as in Instar I but more pronounced, papillae above and along stripes
222 McAlpine, Hubbell, Pliske: Euptychia Vol.14: no.4
more densely set than elsewhere; setae at tips of caudal processes dark brown or black; spiracles as in Instar I.
Length at emergence, 4.5-6.0 mm ; length at end of stadium, 7.5-11 mm. Duration of stadium, 11-16 days.
THIRD INSTAR LARVA (figs. 6, 7). Head and body very slightly deeper lime green and head smaller in relation to body than in Instar II, very densely covered with whitish papillae, those on head with a short brown or black apiculate tip, those on body with whitish translucent tips. Caudal furcate processes somewhat longer and more pointed than in Instar II, brownish or rosy at tips; dorsal prominences of head lobes relatively smaller. Body segments distinctly annulated, except for large areas around spiracles; those areas, except that around prothoracic spiracle, without papillae. Spiracles light yellowish brown with brownish black centers. Substigmatal fold more prominent than in Instar II; venter with setae but without papillae. Coloration as in Instar II except as noted (lime, 9°-ll°, 11-13) ; longitudinal whitish lines somewhat more distinct.
Length at emergence, 7.5-11.0 mm.; length at end of stadium 9.0-13.0 mm. Duration of stadium, 16-27 days.
FOURTH INSTAR LARVA. General appearance, shape, color, and arrangement of papillae and setae much as in Instar III. Base color: lime, 5°-7°, 13-15. Different shades of lime green, in longitudinal bands, now evident. Coloration, proceeding from mid-dorsal line to substigmatal fold, as follows: mid-dorsal line medium lime green; thin whitish line closely parallel to mid-dorsal line; band between last and dorsolat-eral line light lime green; dorsolateral line broad and whitish; a wide upper lateral band of light lime green; a thin mid-lateral whitish line just above spiracles; a narrow medium lime green band; a thin whitish line through the spiracles; a wide lower lateral band of light lime green; a wide whitish band on substigmatal fold. Head of same shade as the medium lime green bands on body.
Length at emergence, 9-13 mm.; length at end of stadium, 11-16 mm. The larva hibernates in this stadium, from early September until late May of the following year.
FIFTH INSTAR LARVA (fig.8). Very similar to Instar IV; surface of head rough, covered with fine green and white papillae tipped with whitish translucent apiculas; papillae more numerous than in Instar IV on both head and body; low conical protuberances at dorsolateral apices of vertex flesh-colored; dorsolateral whitish band wider and anal processes slightly more pointed than in Instar IV, the latter brownish or slightly rosy at tips; ocelli pale shining green, ringed with pale brown. Coloration of body as in Instar IV; dorsolateral band and other whitish lines: lime, 5°-6°, 17-19; light lime green bands: lime, 5°-7°, 13-15; medium lime green bands: lime, 7°-10°, 9-12; head: lime, 8°-10°, 9-11.
Length 11-19 mm. Duration of stadium 15-18 days.
SIXTH INSTAR LARVA (figs.14-16). Very similar in form and coloration to Instar V. Length, 19-28 mm. Duration of stadium, 20-25 days.
PUPA (figs.9, 10, 17, 18). General color light lime green, except abdomen and venation of wing sheaths, which are slightly darker and more bluish; thorax and especially abdomen minutely mottled with pale green or white; abdominal mottling caused by many fine integumental thickenings, which are longitudinally wavy, whitish, and separated by very shallow impressions, not affecting the general smooth appearance of the pupa. Head and mesonotum in side view abruptly truncate cephalad, the truncation straight or weakly concave, at right angles to and strongly rounding into dorsal outline of mesonotum, meeting ventral surface of head shield in an abrupt, slightly acute angle. Dorsum of head sheath planate, its cephalic margin truncate with weak median notch, sides gently divergent cephalad to the moderately acute, prominent anterolateral angles. Mesonotal surface considerably elevated and compressed, forming a mid-dorsal crest which in side view is strongly convex anteriorly. Wing sheaths
1960
Journal of the Lepidopterists' Society
223
slightly raised along anal margin to form a distinct, rather sharply angulate ridge . Frontal transverse ridge, apices of angulate frontal processes, and (sometimes) the elevated margins of wing sheaths slightly tinged with golden brown. Spiracles whitish, inconspicuous; tip of abdomen slightly divided, reminiscent of larval furcate anal process. Length, 10.5-15.5 mm. Duration of stadium, 10-15 days.
ADULT (figs.19, 20). Since the butterfly has been fully described by French, Scudder, and others, and illustrated by Holland, Klots, and Badger, only its variation is here discussed. As Badger has noted, the number of ocelli on the lower surfaces of the wings is somewhat variable. In a series of 40 males and 40 females collected by McAlpine in the Wakelee bog, he found the following variation in this character: fore wing, both sexes, 4 ocelli in most individuals, 3 in a few, 2 in a single specimen; hind wing, males, 5 and 6 ocelli in about equal numbers of specimens; hind wing, females, 6 ocelli in nearly 60% of specimens, 5 in nearly 40%, three specimens with 5 ocelli on one wing and 6 on the other, one specimen with 6 on one wing and 7 on the other. In this series the average wing expanse of males is 32.5 mm., of females 35.4 mm. In a smaller series of males taken by Hubbell and Pliske at Sharon Hollow the wing expanse averages 33.2 mm., with a range of 31.6-34.8 mm. Most of the reared specimens are smaller, the range in Pliske's series being 25.8-30.0, average 28.0, but some of those reared by McAlpine are of normal size.
Literature Cited
Badger, F. S., Jr., 1958. Euptychia mitchellii (Satyridae) in Michigan and Indiana
Tamarack bogs. Lepid. news 12 :41-46, 6 figs. Englehardt, G. P., 1936. Cissia mitchellii in New Jersey. Bull. Brooklyn ent. soc. 31:
110 [additional notes on p.221]. French, G. H., 1889. A new species of Neonympha. Canadian ent. 21 : 25-27. Holland, W. J., 1898. The butterfly hook. New York, Doubleday, Page & Co. xx i+
382 pp., 48 pis., 183 text figs. ................, 1931. The butterfly book, 2nd revised edition. Garden City, N. Y., Double-day, Doran & Co. xii + 424 pp., 77 pis., 198 text figs. Klots, A. B., 1951. A field guide to the butterflies. Boston, Houghton Mifflin Co. xvi +
349 pp., 40 pis. Maynard, C. J., 1891. A manual of North American butterflies. Boston, DeWolfe, Fiske
& Co. iv ,+ 226 pp., 10 pis., 60 text figs. McAlpine, W. S., 1936. [Habitat of Cissia mitchelli in Cass County, Michigan]. Bull.
Brooklyn ent. soc. 31 : 110, 221. Moore, Sherman, 1939. A list of the butterflies of Michigan. Occ. pap. Mus. Zoology
Univ. Michigan 411: 1-23. ................, 1960, A revised annotated list of the butterflies of Michigan. Occ. pap. Mus.
Zoology Univ. Michigan 617 : 39 pp., 1 pi., 1 fig. Pallister, John C, 1927. Cissia mitchellii (French) found in Ohio, with notes on its
habits. Lepidoptera-Satyridas. Ohio journ. sci. 27 : 203-204. Scudder, S. H., 1889. The butterflies of the eastern United States and Canada, with
special reference to Neva England. Cambridge. Author. Vol.3: iv i+ pp. 1775-1958,
89 pis., 2 maps. Skinner, H., 1889. A synonymic catalogue of the North American Rhopalocera. Philadelphia, Amer. Ent. Society, xvi ,+ 100 + xvi pp. Villalobos-Dorninguez, C, & Julio Villalobos, 1947. Colour atlas. (English translation
by A. M. Homer). Buenos Aires, Ateneo Edit.
(WSM) 2501 Bogie Lake Road, Route 5, Milford, Mich., U. S. A.
(SPH) 490 Rock Creek Drive, Ann Arbor, Mich., U. S. A.
(TEP) 960 Forest Road, Barton Hills, Ann Arbor, Mich., U. S. A.
PLATE 1
EUPTYCHIA
3 3 mm.
Figs.l, 2. Instar I larva, July 22, 1958, lateral and dorsal views. Fig.3. Instar I larva, cephalic view of head. Fig.4. Instar I larva, longest and shortest clubbed dorsal setae, greatly enlarged. Fig.5. Instar II larva, 6 August 1958, lateral view. Fig.6. Instar III larva, cephalic view of head. Fig.7. Instar III larva, 15 August 1959, lateral view. Fig.8. Instar V larva (last larval instar of indoor rearings), 5 October 1958, lateral view.
(Drawings from life by S. P. Hubbell)
EUPTYCHIA
PLATE 2
I mm.
0.4 mm.
12
^.■T'WW^
Figs.9, 10. Pupa, 26 October 1958, cephalic and lateral views. Fig.ll. Egg, 10 July 1958, part of surface sculpture, much enlarged. Fig.12. Egg, from above, surface sculpture iodicated only on high-lighted part.
(Drawings from life by S. P. Hubbell)
PLATE 3
EUPTYCHU
Fig.13. Instar I larva, lateral view. Figs.14-16. Instar VI larva, lateral and two dorsal views. Figs. 17, 18. Pupa, dorsal and lateral views. Fig.19. Adult male, Wakelee, Michigan, upper surface. Fig.20. Adult female, Wakelee, Michigan, under surface. (Photographs by W. S. McAlpine)