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108
Field and Technique Notes
Vol.6, nos.6-8
INTERSPECIFIC MATING
Interspecific mating, though used frequently in genetic experiments, is fairly rare in the field. Only crosses between Colias eurytheme Bdv. and C. philodice Latr. are met often, but here the status of these two "species" is still controversial. It may, therefore, be of interest to report a case of mating between two species of Lycaeninae. July 2, 1952, on milkweed (Asclepias), a pair of Coppers was taken in copulation, that were soon diagnosed as a male Bronze Copper, Lycaena thoe Guerin, and a female American Copper, L. phlaeas americana Harris. It would be interesting to test for possible interspecific hybrids experimentally.
Harry SlCHER, Loyola University School of Dentistry, Chicago 12, 111., U.S.A.
MOTHS FEIGNING DEATH
I had some small experiences August 24 with moths at light which may throw some light on this business of feigning death, as it is called.*
The first time I noticed this matter concerned Nephelodes emmedonia Cram., in 1949. Note that this insect appears here in September, rarely in late August.
Up until mid-August this year the weather has been hot most of the time, with warm nights, and I found no accidental incidents of feigning of death among any species taken at light on the screen or walls. The nights of August 22 and 23 this year were very cool: a little over 50° F. on the 23rd, on which night no moths showed up at lights; on the 24th, the day was warm, the sun hot, but at 10:30 P.M. the temperature was 60° F. Just a few moths were at light.
A species of Leucania was shoved into the jar by my finger without any struggle; I shook it back out, but it merely crawled, did not go "dead" but made no attempt to fly. A species of Feltia was even more lax; I picked it up with fingers, put it down, it lay still a second or two then crawled away, not trying flight, and I took it this way two or three times. A Loxostege similalis Guen. was on the window sill. They are usually quick to sense approach, and it is necessary to work fast to take them with the jar as a rule. I nudged this with my finger. It did not move. I simply picked it up with fingers and put it in the jar. It was a quite perfect specimen, though they are common enough here. The degree of day and night temperature seems indeed to be most important to life forces of these creatures. After a hot or warm day they obviously became slow and half dormant on a cool night. Thus Utetheisa bella L. during the hot days in Florida was very alert and hard to take by net, but at light it was attracted to lights on the buildings and was found resting on walls and sidewalks in numbers, quite easily picked up by hand and placed in a jar. Those which are fall species like N. emmedonia, usually flying or living on cool September nights, would suffer from the tendency to become dormant when at rest and perhaps have thus more quickly adopted the habit of lying quite still after dropping when disturbed. The habit obviously differs in intensity in various species, but without doubt is common to many if the circumstances are right. I believe this to be temperature reaction more than anything else.
H. £. WOODCOCK, 6115 Newport Avenue, Chicago, Illinois, U.S.A.
*See Lep. News, vol. 4: p. 46; vol. 6: p. 42.