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Journal of the Lepidopterists' Society 37(4), 1983, 306-309
THE LARVA OF HOMORTHODES FURFURATA (GRT.) (NOCTUIDAE)
Kenneth A. Neil
Department of Biological Sciences, Simon Fraser University, Burnaby, B.C., Canada V5A 1S6
ABSTRACT. The mature larva of Homorthodes furfurata (Grt.) is described and illustrated.
Homorthodes furfurata (Hadeninae) was described by A. R. Grote in 1874 based on material collected at Albany, New York. To date, nothing has been published on the immature stages of this species. Crumb (1956) described the larva of what he thought was H. furfurata based on an incorrect determination of the adults by Benjamin. As shown by Godfrey (1972), Crumb's determination actually applied to the closely related western species H. uniformis (Smith). Rockburne and Lafontaine (1976) gave maple (Acer sp.) as the host plant.
H. furfurata occurs from Nova Scotia (Ferguson, 1954), Maine, Quebec and Ontario, south to Massachusetts, and central New York state (Forbes, 1954). A female H. furfurata was collected at an ultraviolet light on 29 July 1978, 2.5 km south of Tomahawk Lake, Halifax County, Nova Scotia, and over the next week laid 10 eggs in a holding container.
The first instar larvae were confined with both living and dead leaves of maple, oak (Quercus sp.), cherry (Prunus sp.), Osmaronia sp., and Taraxacum officinale Weber as well as an artificial diet based on that of Hinks and Byers (1976). The larvae accepted only living Taraxacum officinale leaves but grew slowly with only two reaching maturity. Both larvae pupated by 10 October due to the constant conditions of laboratory rearing. Neither pupa survived the winter. H. furfurata overwinters as a larva with adults emerging the following July and August.
This paper describes the mature larva of H. furfurata. All illustrations were drawn to scale using a camera lucida and stereomicroscope. The terminology and abbreviations used follow Godfrey (1972).
Homorthodes furfurata (Grote)
General. Head: integument with minute granules; width 8.0 mm. Total length 25.8 mm. Body: integument with minute granules; Ab7-8 distinctly swollen; tapering ceph-alad. Prolegs present on Ab3-6, size increasing posteriorly; those on Ab3 slightly more than Vfe the size of those on Ab6. Crochets uniordinal, 23-25 per third abdominal proleg, 25-29 per fourth, 28-34 per fifth, 33-37 per sixth. All setae simple.
Coloration (living material). Head (Fig. 3): blackish brown with a few black coronal freckles. Body (Figs. 1, 2): blackish, paler on ventral surface. Middorsal and subdorsal lines, whitish, narrow and broken, reduced to a series of dashes. Dorsal and subdorsal setal bases whitish. Spiracles dark orange-brown with black peritremes. Lateral shield of
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(^^fflfflpBBBB^^h
Figs. 1 & 2. Homorthodes furfurata, larva: 1, lateral view; 2, dorsal view (x5.5).
prolegs brownish black. Prothoracic shield orange-brown with lateral and posterior margins black.
Head (Fig. 3). Epicranial suture 0.45 mm long; height of frons (apex to Fa's) 0.49 mm; distance from Fl to anterior edge of clypeus 0.37 mm; interspace between Fl-Fl 0.23-0.25 mm; AFa anterior and AF2 posterior to apex of frons; A1-A3 forming an obtuse angle at A2; Pl-Pl 0.62-0.63 mm; P2-P2 0.64-0.65 mm. Distance from PI to epicranial suture about % that from Pl-L; L cephalad of juncture of adfrontal ecdysial lines. Ocellar spacing: Ocl-Oc2 0.053-0.058 mm; Oc2-Oc3 0.034-0.039 mm; Oc3-Oc4 0.029-0.034 mm.
Mouthparts. Identical to those of H. uniformis. Hypopharyngeal complex (Fig. 4): spinneret very thin, transparent, tapering distally, about 1.5 times the length of Lpsl; Lp2 and about Vfe the length of Lpsl; stipular setae slightly more than lk the length of Lpsl, slightly less than twice the length of Lpl, about equal to Lp2; Lps2 about lk the length of Lpl; distal and proximal regions of hypopharynx continuous, no medial transverse cleft present; distal and proximolateral regions of hypopharynx covered with small fine spines, spines becoming slightly longer proximally. Mandible (Figs. 5, 6): two well-separated outer setae present; inner surface with distinct ridges; lacking inner tooth; with six outer teeth, the sixth rounded and indistinct, the first five angular and well developed; outer margins of all teeth lacking serrations.
Thorax. Segment Tl (Fig. 9): prothoracic shield heavily sclerotized; SD1 and SD2 setal insertions separated from the edge of the prothoracic shield; interspace Dl-Dl about 0.82 XD1-SD1; D2-SD2 about 1.57 SD2-XD2; seta L2 present, much finer than LI; spiracle elliptical, 0.19-0.20 mm high, 0.112-0.117 mm wide; peritreme wider laterally. T2 (Fig. 5): D1-D2 about 0.82 D2-SD2; all setae thin and hairlike, tapering and sharply pointed distally; coxal bases widely separated. T3: Ts3 spatulate (Fig. 9), not tapering distally as in H. uniformis.
Abdomen. Dorsal and lateral chaetotaxy of Abl-10 as in Fig. 9. Abl with 2 SV setae, Ab2-6 with 3 SV setae, Ab7-8 with 1. Ab9: SD1 much finer and hairlike than Dl and D2. AblO: anal shield as in Fig. 8. Dorsal margin convex, posterior margin entire. Length of Dl on Ab6-7 0.240-0.245 mm; D2 0.26-0.27 mm. Asp 7 0.12-0.13 mm high, 0.09 mm wide; Asp8 0.325-0.328 mm high, 0.15 mm wide.
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Figs. 3-9. Homorthodes furfurata, larval structures: 3, head capsule, frontal view; 4, hypopharyngeal complex, left lateral view; 5, left mandible, oral surface; 6, left mandible, outer surface; 7, left mesothoracic tibia and tarsus; 8, anal shield, dorsal view; 9, dorsolateral chaetotaxy of prothoracic (Tl), mesothoracic (T2), and abdominal segments (Abl-2, Ab6-10). Scale lines equal 1.0 mm.
Material examined. 2 specimens: 2.5 km south of Tomahawk Lake, Halifax Co., Nova Scotia. Reared on Taraxacum officinale Weber from ova obtained from a female on 29 July 1978. Larvae pupated 8-10 October 1978. Moth collected, determined, and larvae reared by K. A. Neil.
Remarks. The larvae of H. furfurata and H. uniformis are very similar and based
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on the figures of H. unijormis given by Godfrey (1972), cannot be separated using head capsule and mouthpart structures. The spatulate Ts3 (Fig. 9) can be used to differentiate H. furfurata from H. unijormis, the latter having simple hairlike tarsal setae. Homor-thodes lindseyi (Benjamin) has Ts3 spatulate, but can easily be separated from H. furfurata by the shorter tarsal setae, mandibular, and hypopharyngeal complex differences.
Acknowledgments
I would like to thank Dr. G. L. Godfrey of the Illinois Natural History Survey for reviewing this manuscript, and Ronald Long of Simon Fraser University for photography.
Literature Cited
CRUMB, S. E. 1956. The larvae of the Phalaenidae. U.S. Dept. Agr. Tech. Bull. 1135.
356 pp. Ferguson, D. C. 1954. The Lepidoptera of Nova Scotia: (Macrolepidoptera). Nova
Scotia Mus. Sci. Bull. 2. 214 pp. 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. Grote, A. R. 1874. New species of North American Noctuidae. Proc. Acad. Nat. Sci.
Phil. 26:197-214. 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.