98 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



cf. 



Hydropsyche morosa Hagen 



Hydropsyche morosa Hagen (1861, p. 287); 

 Hydropsyche chlorotica Hagen (1861, p. 290); 



Larva. — Unknown. 



Adults. — Size, color and general struc- 

 ture identical with bifida. Male genitalia, 

 fig. 366, differing from bifida chiefly in the 

 aedeagus, which has the base larger, the 

 stem slightly sinuate, and the membranous 

 dorsal appendages tipped with a flat, sclero- 

 tized denticulate plate. 



We have not taken this species in Illinois 

 in our recent survey, but the locality, 

 "Chicago" was mentioned by Hagen in his 

 original description of chlorotica. These 

 Chicago specimens, however, prove to be 

 females of the genus Cheumatopsyche so 

 that we still have no definite record for the 

 state. 



The species is known from Michigan, 

 New York, Ontario, Virginia and West 

 Virginia and may ultimately be found in 

 Illinois. 



Hydropsyche bronta Ross 



Hydropsyche bronta Ross (1938«, p. 149); 

 cf , 9. 



Larva. — Length 14 mm. In coloration 

 similar to bifida, especially with reference 

 to the checkered type of pattern on the 

 head. As with bifida, there is considerable 

 variation in the details of this pattern. 



Adults. — In size, color and general struc- 

 ture similar to bifida. Male genitalia, fig. 

 364, with apical processes of tenth tergite 

 short and finger-like; apical segment of 

 claspers conical; aedeagus with dorsal mem- 

 branous processes tipped by a long, spinose 

 spur which is directed ventrad and projects 

 considerably beyond the ventral margin of 

 the stem. Female genitalia similar in gen- 

 eral with those of bifida, differing in charac- 

 ters of the clasper receptacle, fig. 3875. 



In Illinois this species is restricted with 

 few exceptions to small and medium-sized 

 streams in northern Illinois. Most of these 

 are spring fed ; all are permanent. The 

 adults emerge from April to the latter part 

 of August. 



The range of the species includes most of 

 the Northeast, as follows: Illinois, Mary- 

 land, Michigan, New Brunswick, Ohio, On- 



tario, Pennsylvania and Virginia ; in addi- 

 tion we have a large collection from Wy- 

 oming. 



Illinois Records. — Many larvae, taken 

 March 2 to May 30, and many females and 

 two pupae, taken April 25 to August 23, are 

 from Amboy (Green River), Apple River 

 Canyon State Park, Cedarville, Council 

 Hill (Galena River), Elgin (Botanical 

 Gardens), Fox Lake, Galena (Sinsinawa 

 River), Havana (Quiver Creek), Leland, 

 Marengo, Momence, Mount Carroll, Ore- 

 gon, Rock City, Sycamore (tributary South 

 Kishwaukee River), Utica (Split Rock 

 Brook), White Pines Forest State Park, 

 Wilmington. 



Hydropsyche cheilonis Ross 



Hydropsyche cheilonis Ross (1938^, p. 149); 

 cf , 9. 



Larva. — Similar to bifida in size and 

 color, especially in the checkered head pat- 

 tern, as in fig. 356. 



Adults. — In size, color and general struc- 

 ture identical with bifida. Male genitalia, 

 fig. 365, differing from those of bronta chief- 

 ly in aedeagus, which has shorter mem- 

 branous lobes tipped by a narrow spur con- 

 stricted at the base ; in addition, the apical 

 bulb of the aedeagus has four pockets (two 

 meso-dorsal and two lateral), each bearing 

 a group of at least 6 relatively long and 

 heavy sclerotized spicules, the lateral pockets 

 exserted on a short stalk. Female typical 

 for the bifida group, genitalia as in fig. 

 387D. 



To date this species has been found in 

 Illinois only in the Middle Fork and Salt 

 Fork of the Vermilion River in the neigh- 

 borhood of Oakwood. In these streams 

 this species is fairly abundant, and the only 

 member of the bifida group occurring in 

 them. A scattering of adults has been taken 

 from May 4 to September 20. 



Practically nothing can be stated regard- 

 ing the range of this species, since we have 

 only two records from Michigan (Aurelius 

 and East Lansing) in addition to the Illi- 

 nois records. This indicates a spotted and 

 local distribution pattern. 



Illinois Records. — Muncie: Sept. 20, 

 1935, Frison & Mohr, 2$ ; May 4, 1936, 

 Ross & Burks, 1 $ ; July 6, 1936, Mohr & 

 Burks, 1 larva. Oakwood: Salt Fork Riv- 

 er, July 18, 1933, Ross & Mohr, Z$, 79, 



