40 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



the Ozarks and neighboring hills of near- 

 by states. These resemble our Illinois form 

 in size and color, but are readily separable 

 on the basis of male genitalia as follows: 



Claspep 



Fig. 141. — AgapetHs artesus. 



Agapetus illini Ross 



Agapetus illini Ross (1938rt, p. 106); cf, 9. 



Larva. — -Similar in size and color to that 

 of Glossosoma. 



Adults. — Length 7-8 mm. Body and ap- 

 pendages dark brown. Male genitalia, fig. 

 144, with apex of tenth tergite irregularly 

 and sharply serrate, claspers tapering to 

 apex. Female genitalia as in fig. 145. 



Restricted in Illinois to clear streams in 

 the Ozarkian region, where it becomes very 

 abundant in early spring in these temporary 

 streams. It has one generation per year. 



Known also from Arkansas, Kentucky, 

 Missouri and Oklahoma; apparently con- 

 fined to the Ozarkian uplift and adjacent 

 hilly regions. 



Illinois Records. — East of Aldridge: 

 May 14, 1940, Mohr & Burks, 3 pupae, 

 many larvae. Alto Pass, Union Spring: 



cf Genitalia 

 Fig. 143. — Agapetus medicus. 



artesus, fig. 141, known from Missouri, has 

 a somewhat pear-shaped, pointed tenth 

 tergite and medium length, rounded clasp- 

 ers; crasmus, fig. 142, known from Tennes- 

 see, has a long tenth tergite with a hook at 

 apex and very short, truncate claspers; and 

 medicus, fig. 143, known from Arkansas, 

 has a cleaver-shaped tenth tergite and long, 

 rectangular claspers. Satisfactory charac- 

 ters have not yet been found to identify the 

 females of species in this group. 



Fig. 144. — Agapetus illini. 



Fig. 145. — Agapetus illini, female genitalia. 



