August, 1944 



Ross: Caddis Flies of Illinois 



221 



Vorhies (1909) described all stages of this 

 insect under the name uwarowii. 



In Illinois the species centers around the 

 glacial lakes in the northeastern part of 

 the state. In these it is very abundant, being 

 found under stones and among weeds near 

 the shore. Our adult emergence records, 

 including those from other states, extend 

 from June to September, indicating more 

 than one generation per year. 



The species ranges widely through the 

 North and Northeast; records are avail- 

 able from Illinois, Michigan, New Bruns- 

 wick, New York, Ontario, Pennsylvania, 

 Saskatchewan and Wisconsin. The range 

 may be more extensive southward, but I 

 have restricted identifications of this species 

 to specimens about which there seems no 

 doubt. 



Illinois Records. — Many males, females 

 and pupae, taken May 18 to August 14, 

 and many larvae and cases, taken May 15 

 to June 11, are from Algonquin, Antioch, 

 Aurora, Channel Lake, Chicago, Fox Lake, 

 Grass Lake, Havana, Ottawa, Pistakee 

 Lake, Richmond, Round Lake, Sand Lake, 

 Spring Grove (Nippersink Creek), Volo, 

 Zion (Dead River). 



Leptocella species a 



Larva. — Length 12 mm. Head and pro- 

 notum with a mottling of brown and yellow 

 very similar to that in diarina. Mesonotum 

 yellow with brownish marks as in the same 

 species. Legs yellow, the middle and hind 

 pair with narrow black bands at apex. Hind 

 legs with swimming brush of long hairs. 



This larva has not been reared, nor have 

 we any evidence which would link it with 

 species known only from the adults. We 

 have one larva from Illinois, from the Spoon 

 River near Havana, October 2, 1938, B. D. 

 Burks; in addition, material has been taken 

 in Wisconsin and Michigan. 



Athripsodes Billberg 



Athripsodes Billberg (1820, p. 94). Geno- 

 type, by subsequent designation ot Milne 

 (1934, p. 18): Phryganea albifrons Linnaeus. 



The larva is short and builds either a 

 tapering, horn-shaped case, fig. 810, or one 

 with lateral flanges, figs. 808, 809; gills are 

 usually abundant and tufted, although diffi- 

 cult to distinguish and reduced in number in 

 some forms; the mouthparts are short, the 



mandibles with a blunt, toothed apex. The 

 adults are brown or black, with wide hind 

 wings. 



A large number of species have been de- 

 scribed from North America, of which 14 

 have been collected in Illinois. Eight species 

 are known from the larval stage, and three 

 additional unassociated forms have been rec- 

 ognized; characters have been found for 

 separating these to species and also for sep- 

 arating the females for all the Illinois spe- 

 cies in which this sex is known. 



KEY TO SPECIES 



Larvae 



1. Mesonotum with man)- hairs, fig. 763; 



paratrontal areas originating at apex 



of frons mentieus, p. 232 



Mesonotum with only two or three 

 pairs of scattered hairs, fig. 765; 

 parafrontal areas, if present, origi- 

 nating below apex of frons, fig. 764 2 



2. Parafrontal areas absent, head pale 



without distinct markings 



sp. a, p. 235 



Parafrontal areas outlined distinctly 

 at least somewhere along their 

 boundary, fig. 764 3 



3. Head dark brown except tor distinct 



pale lines on "false frons" and side, 

 fig. 766; case with extended lateral 



margin, fig. 808 4 



Head either yellowish, or brown with 

 many pale spots, fig. 764; case usu- 

 ally without extended lateral mar- 

 gin, fig. 810 5 



4. Case twice as long as wide, fig. 808; 



frons nearly black ancylus, p. 227 



Case broader, only one and one-half 

 times as long as wide, fig. 809; frons 

 reddish brown Pfiavus, p. 228 



5. Sclerotized bars of mesonotum wide, 



with a mesal spur and a thickened 

 area down the center, fig. 769; pro- 



notum chocolate brown 



sp. c, p. 236 



Sclerotized bars of mesonotum linear, 

 without a mesal spur or thickened 

 central area, fig. 764; pronotum 

 yellowish brown to colorless 6 



6. Ninth segment with only weak, short 



setae, variable in number, fig. 771. . 7 

 Ninth segment with two dorsal pairs 

 of long, black setae, fig. 770 8 



7. Head with parafrontal areas nearly as 



wide as frons, fig. 772 sp. b, p. 235 



Head with parafrontal areas much nar- 

 rower than frons, fig. 773 



dilutus, p. 231 



