78 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



Fig. 291. — Hydropsyche cheilonis larva, 

 stridulator of front leg. 



Fig. 292. — Smicridea Jasciatella larva, strid- 

 ulator of front leg. 



Fig. 293. — Hydropsyche cheilonis larva, pro- 

 sternal plates. 



Fig. 294. — Cheumatopsyche campyla larva, 

 prosternal plates. 



Fig. 295. — Parapsyche cardis larva, head, 

 ventral aspect. 



Fig. 296. — Arctopsyche sp. larva, head, ven- 

 tral aspect. 



Fig. 297. — Diplectrona modesta larva, head, 

 ventral aspect. 



Fig. 298. — Parapsyche cardis larva, gill with 

 terminal branches. 



Fig. 299. — Diplectrona modesta larva, gill 

 with terminal branches. 



304 



305 



Fig. 300. — Parapsyche cardis larva, portion 

 of abdomen. 



Fig. 301. — Arctopsyche sp. larva, portion of 

 abdomen. 



Fig. 302. — Potamyia flava larva, submen- 

 tum (sm). 



Fig. 303. — Diplectrona modesta larva, sub- 

 mentum (sm). 



Fig. 304. — Diplectrona modesta larva, head, 

 dorsal aspect. 



Fig. 7>^^.— Smicridea jasciatella larva, head, 

 dorsal aspect. 



fig. 297; each branched gill with 

 branches arising from both sides 

 and top of basal stalk, fig. 299 7 



6. Gula rectangular and of even width, 



fig. 295; abdomen with stout, short, 

 black, scalelike hairs arranged in 

 tufts along dorsum near sides, fre- 

 quently with broad scales scattered 



between them, fig. 300 



Parapsyche, p. 83 



Gula narrowed posteriorly, fig. 296; 

 abdomen without distinct setal 

 tufts, with coarse hairs of varying 

 lengths, some ot them scalelike but 



narrow and long, fig. 301 



. Arctopsyche, p. 83 



7. Mandibles with winglike dorso-lateral 



flanges along basal half, fig. 283; 



submentum cleft, fig. 302 



Potamyia, p. 85 



Mandibles without distinct dorso-lat- 



eral flanges, fig. 286; submentum 

 sub-conical, not cleft, fig. 303 8 



8. Frons expanded laterad, its lateral ex- 

 tensions sharp, fig. 304 



Diplectrona, p. 84 



Frons not expanded laterad, its lateral 

 extensions scarcely produced, fig. 

 305 Smicridea, p. 85 



Pupae 



A''. B. — In connection with this key, characters 

 of the mandibles should be used Jor checking 

 identifications, fig. 316. 



1. Apical processes sharply recurved, fig. 

 3065, excavated along caudo-ven- 

 tral aspect and tip without points, 



fig. 306 Parapsyche, p. 83 



Apical processes not rec.urved, fig. 307, 

 either not excavated along caudo- 

 ventral aspect or with tip bifid. ... 2 



