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Journal of the Lepidopterists Society 37(3), 1983, 249-252
THE LARVA OF SIDERIDIS MARYX (GUENEE) (NOCTUIDAE)
Kenneth A. Neil
Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
ABSTRACT. The mature larva of Sideridis maryx (Guenee) (Noctuidae) is described and illustrated.
The noctuid genus Sideridis (Hiibner) (Hadeninae) is represented in eastern North America by three species, S. rosea (Harvey), S. congermana (Morrison), and S. maryx (Guenee) (Forbes, 1954). Of the three species, S. rosea is the most common, and the immature stages are best known; they were most recently described and illustrated by Godfrey (1972) who listed grass, dandelion, Elaeagnus angustifolia L., Ribes sp., Shepherdia sp., and Salix sp. as host plants. S. congermana and S. maryx are generally considered to be uncommon to rare throughout eastern North America (Forbes, 1954; Rockburne & Lafontaine, 1976). Dyar (1899) briefly described the mature larva of S. maryx (=Ma-mestra rube fact a Morrison) based on preserved material. The larva of S. congermana and the natural host plants of all three species of Sideridis are unknown.
This paper describes the mature larvae of S. maryx reared from ova obtained from a female taken on 11 June 1979 at Belliveau Cove, Digby Co., Nova Scotia. Larvae were fed an artificial diet based on that of Hinks and Byers (1976). They grew quickly and pupated by 7 August. Adults emerged 10-15 September 1979. Throughout its range, S. maryx is single brooded, overwintering as a pupa, with adults emerging in late spring and early summer.
The terminology and abbreviations used here follow Godfrey (1972). The illustrations which accompany the description of the last larval instar were drawn to scale using a camera lucida and stereomicroscope.
Sideridis maryx (Guenee)
General. Head 3.5-4.0 mm wide. Total length 40.0-49.5 mm. Head and body smooth. Prolegs present on Ab3-6, size increasing posteriorly on Ab3-6, those on Ab3 slightly more than V2 the size of those on Ab6. Crochets uniordinal, 19-22 per third abdominal proleg, 21-25 per fourth, 26-29 per fifth, 27-30 per sixth. All simple.
Coloration (living material). Head (Fig. 3): yellowish brown with darker reddish brown coronal reticulations and coronal stripes. Body (Figs. 1, 2): red; dorsal and subdorsal areas with numerous greyish flecks, flecks heaviest at edges of middorsal line; middorsal and subdorsal lines narrow and poorly defined, the middorsal line more well defined on Tl-3; lateral and ventral areas translucent red, lacking greyish flecks. Spiracles yellowish brown with black peritremes. Lateral shields of prolegs and thoracic legs yellowish brown, both darker basally. Prothoracic shield orange brown.
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Figs. 1 & 2. Sideridis maryx, sixth instar larva (x3): 1, dorsal view; 2, lateral view.
Head (Fig. 3). Epicranial suture 0.92-1.05 mm long; height of frons (apex to Fa's) 1.03-1.05 mm; distance from Fl to anterior edge of clypeus 0.33-0.35 mm; interspace between Fl-Fl 0.45-0.47 mm; aFa anterior and Af2 posterior to apex of frons; A1-A3 forming an obtuse angle at A2; Pl-Pl 1.54-1.56 mm; P2-P2 1.70-1.72 mm. Distance from PI to epicranial suture less than that from PI to L; L cephalad of juncture of adfrontal ecdysial line. Ocellar spacing: Ocl-Oc2 0.07-0.09 mm; Oc2-Oc3 0.10-0.12 mm; Oc3-Oc4 0.05-0.06 mm.
Mouthparts. Hypopharyngeal complex (Fig. 4): spinneret short and broad, subequal to Lpsl; Lpsl longer than Lp2; stipular setae short, about Vs the length of Lpsl, slightly shorter than Lpl, and about V5 the length of Lp2; Lps2 subequal to Lpl; distal and proximal regions of hypopharyngeal complex separated by a distinct medial transverse cleft; distal region with distal V2 bare, remainder with short thin spines becoming longer and slightly more robust proximally; proximolateral region with 15-20 stout spines. Mandible (Figs. 5 & 6): two well-separated outer setae present; inner surface with ridges and tooth; inner tooth prominent, base broad, apex truncate; first outer tooth well developed, serrated on outer side; second outer tooth serrated on side opposite outer tooth; third and fourth outer teeth acutely angular; fifth outer tooth wide and flat with outer margin serrated.
Thorax. Segment Tl (Fig. 8): prothoracic shield weakly sclerotized; SD1 and SD2 setal insertations well separated from shield; interspace Dl-Dl about 0.65 XD1-XD1; D2-SD-2 about 1.41 SD2-XD2; spiracle elliptical, 0.44-0.48 mm high, 0.27-0.29 mm wide;
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Figs. 3-8. Sideridis maryx, larva: 3, frontal view of head capsule; 4, left lateral view of hypopharyngeal complex; 5, oral surface of left mandible; 6, outer surface of left mandible; 7, dorsal view of anal shield; 8, dorsolateral chaetotaxy of prothoracic (Tl), mesothoracic (T2), and abdominal segments (Abl-2, Ab6-10). Scale lines equal 1.0 mm.
peritreme wider laterally. T2 (Fig. 8): D1-D2 about 0.69 D2-SD2; all setae thin and hairlike, tapering and sharply pointed distally; coxal bases narrowly separated.
Abdomen. Dorsal and lateral chaetotaxy of Abl-10 as in Fig. 8. Abl with 2 SV setae, Ab2-6 with 3 SV setae, Ab7-8 with 1. Ab9: SD1 much finer than Dl and D2. AblO: Anal shield as in Fig. 7. Dorsal margin convex, posterior margin entire. Length of Dl on Ab6-7 0.49-0.53 mm; D2 0.56-0.60 mm. Asp7 0.36-0.37 mm high, 0.21 mm wide; Asp8 0.49-0.50 mm high, 0.27 mm wide.
Material examined. 4 specimens: Belliveau Cove, Digby Co., Nova Scotia. Reared on artificial diet (Hinks & Byers, 1976) from ova obtained from a female taken on 11 June 1979. Adults emerged 10-15 September 1979. Moth collected, determined, and larvae reared by K. A. Neil.
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Remarks. Based on the larval description and illustrations of S. rosea given by Godfrey (1972), S. maryx can easily be distinguished from that species by the truncate inner mandibular tooth, the short, stout spinneret which is only about V2 the length of the spinneret of S. rosea, and by the wider Fl-Fl interspace.
Acknowledgments
I thank Dr. G. L. Godfrey of the Illinois Natural History Survey for reviewing this manuscript and Ronald Long of Simon Fraser University for photographing the illustrations.
Literature Cited
Dyar, H. G. 1899. Descriptions of the larvae of fifty North American Noctuidae. Wash.
Entomol. Soc. Proc. 4:315-332. Forbes, W. T. M. 1954. Lepidoptera of New York and neighboring states. Pt. III.
Cornell Univ. Agr. Expt. Sta. Mem. 329. 433 pp. Godfrey, G. L. 1972. A review and reclassification of larvae of the subfamily Had-
eninae (Lepidoptera, Noctuidae) of America north of Mexico. U.S. Dept. Agr. Tech.
Bull. 1450. 265 pp. HiNKS, C. F. & J. R. Byers. 1976. Biosystematics of the genus Euxoa (Lepidoptera:
Noctuidae). V. Rearing procedures and life cycles of 36 species. Can. Entomol. 108:
1345-1357. Rockburne, E. W. & J. D. Lafontaine. 1976. The cutworm moths of Ontario and
Quebec. Can. Dept. Agr. Publ. 1593. 164 pp.