August, 1944 



Ross: Caddis Flies of Illinois 



259 



Arcadopsyche Banks (1930^, p. 129). Geno- 

 type, monobasic: Arcadopsyche prominens 

 Banks. New synonymy. 



Oligopsyche Carpenter (1933, p. 36). Geno- 

 type, by original designation: Notiopsyche 

 Carolina Banks. New synonymy. 



Neuropsyche Carpenter (1933, p. 38). Geno- 

 type, by original designation: Neuropsyche 

 tibialis Carpenter. New synonymy. 



Jenortha Milne (1936, p. 119). Genotype, 

 monobasic: Jenortha cascadensis Milne. New 

 synonymy. 



This genus is characterized in the adults 

 by the arrangement of warts as outlined in 

 the key. The females exhibit few characters 

 upon which to base their classification, and 

 to date I have been able to find no differ- 

 ences upon which to key most of them to 

 species. Comparative lengths of the antennal 

 segments, slight differences of venation, and 

 some fairly striking differences in the female 

 genitalia can be used to segregate the species 

 into groups containing two or more. It is 

 usually necessary, therefore, to rely upon 

 association with males for specific identifi- 

 cation of females. 



An astonishing number of bizarre charac- 

 ters have been developed by the males. Some 

 have leaflike legs, others extremely wide 

 wings or folded-back portions which form 

 large pockets filled with black scales; still 

 others have the maxillary palpi variously 

 developed into spoon-shaped structures with 

 long extensile membranous organs. Organ- 

 izing and correlating the differences found 

 in both male and female genitalia give us 

 ample evidence that this entire complex is a 

 compact phylogenetic group. The secondary 

 sexual characters so strikingly developed in 

 the males appear to have no relation to the 

 phylogeny of the true species groups in 

 the genus. It seems necessary, therefore, 

 to consider this entire complex one genus. 



There are about 25 well-recognized spe- 

 cies in the Nearctic region. Only one has 

 been found in Illinois, but at least a dozen 

 others have been taken in the eastern and 

 northeastern states. Their distribution, 

 however, is so local, especially west of the 

 Alleghenies, that it is impossible to predict 

 which ones might possibly be taken in Illi- 

 nois with additional collecting. 



An interesting feature of the genus is the 

 local nature of many colonies. Only rarely 

 are many species found occurring together 

 in the same locality. Most species prefer 

 streams or springs to lakes. 



Lepidostoma liba Ross 



Lepidostoma liba Ross (1941/^, p. 120); d^, 

 9. 



Larva. — Fig. 882. Length 7.5 mm. Head, 

 pronotum and metanotum dark chocolate 

 brown; legs yellowish brown; the head has 

 a pattern of small, lighter brown markings. 

 Frontal area of head nearly flat, frons of 

 only medium width; upper portion of head 

 without long setae. Pronotum with an 

 apical row of long setae and a few scattered 

 ones in the middle. Mesonotum with an 

 irregular group of setae around periphery. 

 Metanotum with two pairs of small central 

 dark spots, each bearing a long seta, and a 

 longer lateral sclerite bearing several setae. 

 Middle and hind legs slender anci of medium 

 length, front legs stout and short. 



Case. — Length 8 mm. Two distinct types 

 are built, a square log-cabin type of wood 

 fragments and a round type of stones. Both 

 have a rough exterior, and frequently a 

 case will be part one and part the other. 



Adults. — Length 8.5-9.0 mm. Color var- 

 ious shades of brown, the dorsum darker, 

 antennae, legs and venter much lighter, 

 often tawny; the wings have patches of light 

 hair which give the species an indistinctly 

 checkered appearance. Male genitalia, fig. 

 883 : ninth tergite with two large brushes 

 of long setae, tenth tergite with a pair of 

 lateral sclerotized irregular and short arms, 

 and a pair of mesal, membranous triangular 

 lobes; claspers with a long curved dorso- 

 basal hook; from ventral view they appear 

 slightly constricted just before apex, the 

 apex itself irregular and oblique. Female 



Fig. 882. — Lepidostoma liba, larva. 



