22 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



nois Natural History Survey at Urbana. 

 Some material is cited which belongs to 

 other institutions, and this is usually indi- 

 cated by letters following the record ; these 

 letters are as follows: 



BC — Betten Collection, Ithaca, New York. 



UM — University of Minnesota, St. Paul, 

 Minnesota. 



FM — Chicago Natural History Museum, 

 Chicago, Illinois (formerly Field Museum). 



MCZ — Museum of Comparative Zoology, 

 Cambridge, Massachusetts. 



Records Outside Illinois 



Many records for states other than Illi- 

 nois which are cited in this report are the 

 first for these states. Those not taken from 

 the literature are from Illinois Natural 

 History Survey files, which are accessible 

 for procuring additional locality and season- 

 al data. 



KEY TO FAMILIES 

 Larvae 



L Pro-, meso- and metanotum each with 

 a single, sclerotized shield embracing 



the entire notum, fig. 557 2 



Either meso- or metanotum or both 

 without sclerites or with sclerotized 

 shield subdivided into separated 

 plates, figs. 36, 37 3 



2. Abdomen with many conspicuous 



branched gills, fig. 281; larva living 



in a nest, fig. 4 



Hydropsychidae, p. 76 



Abdomen without gills; larva living in 



a definite case, fig. 465 



Hydroptilidae, p. 117 



3. Anal legs projecting beyond, and free 



from, membranous lobes of tenth 

 segment, fig. 22; note especially 



fig. 23 _. ; 4 



Anal legs appearing as lateral sclerites 

 of membranous lobes of tenth seg- 

 ment, fig. 20 6 



4. Sclerotized shield present on dorsum of 



ninth abdominal segment, fig. 22. . 



Rhyacophilidae, p. 30 



Dorsum of ninth abdominal segment 

 entirely membranous 5 



5. Labrum with anterior and lateral por- 



tions expanded into a wide, mem- 

 branous area, fig. 24 



Philopotamidae, p. 44 



Labrum shorter, entirely sclerotized, 

 fig- 25 Psychomyiidae, p. 51 



6. Claws of hind legs very small, those of 



middle and front legs large, fig. 26. . 



Molannidae, p. 205 



Claws of hind legs as long as those of 

 middle legs, fig. 27 7 



7. Antennae long, at least eight times as 



long as wide, and arising at base of 



mandibles, fig. 28 



Leptoceridae, p. 209 



Antennae much shorter, fig. 709, not 

 more than three or four times as 

 long as wide, often very inconspicu- 

 ous, and arising at various points, 

 figs. 29, 30 8 



8. Mesonotum submembranous except 



for a pair of parenthesis-like, scle- 

 rotized bars as in fig. 764 



Leptoceridae, p. 209 



Mesonotum without such bars 9 



9. Meso- and metanotum entirely mem- 



branous or with only minute scle- 

 rites, figs. 561-566 



Phryganeidae, p. 161 



Mesonotum and usually metanotum 

 with some conspicuous sclerotized 

 plates 10 



10. Labrum with a row of about 20 stout 



setae across middle, fig. 31 



Calamoceratidae, p. 209 



Labrum without such a row of setae, 

 usually with 6-8 long setae, not in a 

 row, and other scattered small setae, 

 fig. 32 11 



11. Anal hooks with a long comb of teeth, 



fig. 33; larva living in a case shaped 

 exactly like a snail shell, fig. 906. . . 



Helicopsychidae, p. 266 



Anal hooks with accessory teeth, but 

 these not forming a comb, fig. 34; 

 case not at all snail-like 12 



12. Metanotum with a wide, straplike an- 



terior sclerite, a pair of oblong lateral 

 sclerites and a posterior thin sclerite, 

 as in fig. 36, the posterior sclerite 

 frequently difficult to distinguish.. 



Odontoceridae, p. 209 



Metanotum not with this grouping of 

 sclerites, usually with only 1 or 2 

 round, small and more or less indefi- 

 nite sclerites, fig. 37 13 



13. Anal hooks formed of 2 or 3 long teeth 



situated one over another, fig. 35. . 



Sericostomatidae, p. 266 



Anal hooks formed of a single large 

 tooth with 1 or more small teeth on 

 its dorsal edge, fig. 34 14 



14. Pronotum with a deep furrow running 



almost the full width of the sclerite, 

 figs. 892, 896, 897, the posterior mar- 

 gin of the furrow forming a sharp and 



slightly overhanging carina 



Brachycentridae, p. 260 



Pronotum either without any trace of a 



