August, 1944 



Ross: Caddis Flies of Illinois 



253 



males, taken May 18 to August 20, and 

 many larvae, taken May 16 to June 12, 

 are from Antioch, Channel Lake, Fox Lake, 

 Grass Lake, Grayslake, Pistakee Lake, 

 Richmond, Round Lake, Urbana, Wilming- 

 ton, Zion. 



Triaenodes species a 



Female. — Length 9 mm. Color tawny 

 with the brown and cream pattern typical 

 of the tarda group. Female genitalia, fig. 

 857: apex of ninth sternite not greatly 

 produced, typical in general form of the 

 tarda group; tenth tergite without conspicu- 

 ous apodemes; bursa copulatrix with its 

 ventral bands folded, long and shelflike and 

 heavily sclerotized; the hook set in the apex 

 of the bursa is very heavily sclerotized, 

 especially the margins of the base, giving 

 it a hollow appearance from ventral view. 



We have taken only one female of this 

 species, from Herod, Illinois, May 29, 1935, 

 Ross & Mohr. We have taken no male 

 which could be positively associated with it, 

 but it is definitely none of the other species 

 of which we have record from the state. 

 There is a possibility that it may be the 

 female of phalacris or dipsia, both taken 

 from southern Ohio, or it may be an entirely 

 different species. 



Triaenodes species b 



Larva. — Fig. 838. Length 10 mm. 

 Ground pattern of sclerites straw color; 

 head with spots coalesced to form a pair 

 of long, broad lines down the central por- 

 tion and a pair of short, broad lines on the 

 lateral margin, the ventral aspect almost 

 all dark so that only narrow pale areas 

 appear between the ventral and lateral dark 

 markings; pronotum mostly brown with a 

 pale mesal line, a pale postero-mesal area 

 and a pair of pale lateral spots. Case typi- 

 cal for genus. 



This is an unreared larva of which we 

 have taken only one specimen, from Herod, 

 Illinois, May 15, 1941, Mohr & Burks. 

 It probably belongs to one of the species 

 recorded from southern Illinois on the basis 

 of adults, including perna and species a. 



Mystacides Berthold 



Mystacides Berthold (1827, p. 437). Geno- 

 type, by present designation: Phryganea longi- 



cornis Linnaeus, one of species first included in 

 the genus by Burmeister (1839, p. 918). 



Species of this genus construct a long, 

 slender, parallel-sided case adorned with 

 irregular pieces of leaf, wood or shell frag- 

 ments; the case is not very rigid. The lar- 

 vae have a distinct, rectangular gula, man- 

 dibles which are blunt at apex and armed 

 with several teeth, and single abdominal 

 gills varying in number, usually inconspic- 

 uous. 



Three species are known from North 

 America, of which we have two in Illinois, 

 both restricted to the northeastern corner 

 of the state. 



KEY TO SPECIES 

 Larvae 



Head with a Y-shaped black mark 

 following epicranial stem and arms, 

 fig. 864 longicornis, p. 255 



Head with spots or parallel black lines, 



not forming a Y, fig. 865 



sepulchralis, p. 254 



Adults 



1. Genitalia with a large ventral furca, 



figs. 866, 867 (males) 2 



Genitalia without a ventral furca, fig. 

 868 (females) 3 



2. Apical process of ninth sternite forked, 



the arms long and slender, fig. 866 

 sepulchralis, p. 254 



864 



Fig. 864. — Mystacides longicornis larva. 

 Fig. 865. — Mystacides sepulchralis larva. 



