26 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



fifth and sixth segments wide, with 



4 to 8 hooks, fig. 47 



Molannidae, p. 205 



First abdominal tergite without a ledge 

 except at apex, fig. 20; sclerotized 

 plates of fifth and sixth segments 

 narrow, some or all with only 2 

 or 3 hooks, fig. 48 8 



8. Apical processes of abdomen narrow 



and finger-like, and with apical black 

 hairs as long as the process, fig. 49. 



Helicopsychidae, p. 266 



Apical processes of abdomen either not 

 finger-like, or without long, apical 



hairs, figs. 721-726 



Leptoceridae, p. 209 



9. Abdomen without a fringe of hair; 



apical processes as in figs. 205-207 



,. . . Psychomyiidae, p. 51 



Abdomen with a lateral fringe of hair, 

 fig. 39 10 



10. Abdomen with a pair of almost linear, 



transverse lines of hooks (plate 5P) 

 between fifth and sixth tergites, figs. 



888, 889 Brachycentridae, p. 260 



Abdomen with these areas of hooks 

 not as thin, at least as broad as in 

 fig. 618 11 



11. Apical processes of abdomen short and 



stubby, appearing platelike from 



dorsal view, figs. 570, 571 



Phryganeidae, p. 161 



Apical processes of abdomen finger- 

 like, at least as long as in fig. 50, 

 often styliform, fig. 49 12 



12. Apical processes of abdomen short, 



widely separated and bearing black 

 spines many times as long as the 



processes, fig. 50 



Lepidostomatidae, p. 258 



Apical processes either close together 

 or much longer, figs. 51-54 13 



13. Mandibles produced at apex into a 



narrow, whiplike style, fig. 55 



Odontoceridae, p. 209 



Mandibles pointed but not produced 

 into a style, figs. 56, 57 14 



14. Dorsum of abdomen with transverse 



patches of dense, fine hair, these • 

 patches forming bands on some seg- 

 ments, fig. 58 



Calamoceratidae, p. 209 



Dorsum of abdomen without patches 

 of hair, with only isolated setae, fig. 

 20 15 



15. Apical processes with slender, terminal 



appendage, fig. 52 



Sericostomatidae, p. 266 



Apical processes without appendage. . 16 



16. Antennae twice length of body, looped 



several tim.es around apical processes 

 Leptoceridae, p. 209 



Antennae much shorter, not looped 



around apical processes 17 



17. Apical processes extremely slender at 

 apex, threadlike and sinuate, fig. 53 



Goeridae, p. 256 



Apical processes not greatly narrowed 

 at apex, with apical hairs and not 

 sinuate, fig. 54. . Limnephilidae, p. 176 



Adults 



1. Mesoscutellum with posterior portion 

 forming a triangular, flat area with 

 steep sides, figs. 438-446; mesoscu- 

 tum without warts; front tibiae 

 never with more than 1 spur. Small, 

 hairy individuals not over 6 mm. 



long Hydroptilidae, p. 117 



Either mesoscutellum evenly convex, 

 without a triangular posterior por- 

 tion set off by sharp sides, figs. 80, 

 83, or mesoscutum with warts, figs. 



Fig. 55. — Psilotreta sp. pupa, mandible. 



Fig. 56. — Sericostoma sp. pupa, mandible. 

 (After Ulmer.) 



Fig. 57. — Goera sp. pupa, mandible. (After 

 Ulmer.) 



Fig. 58. — Calamoceratidae sp. pupa, dorsum 

 of abdomen. 



