44 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



Protoptila erotica Ross 



Protoptila erotica Ross (1938a, p. 113); cT, 



9. 



Larva. — Not associated, but undoubtedly 

 present in material collected from the Kan- 

 kakee River and undifferentiated from jnac- 

 ulata. 



Adults. — Length 3.0-3.5 mm. Head and 

 body brown, front wings with a narrow, 

 light band across "cord." Male genitalia, 

 fig. 146: eighth sternite short and scoop- 

 like; tenth tergite divided into a pair of 

 beaklike processes; aedeagus with a large, 

 ovoid, internal lobe, a pair of lateral, style- 

 bearing arms and a heavy, angled central 

 portion. Female genitalia as in fig. 151. 



This widely distributed northern species 

 has been taken only at Momence, along the 

 Kankakee River, in which the larvae un- 

 doubtedly live in company with maculata. 

 Adult records from May to August indicate 

 two or more generations per year. 



Known from Illinois, Wisconsin and Wy- 

 oming. 



Illinois Records. — Momence: Aug. 21, 



1936, Ross & Burks, 6$ ; Kankakee River, 

 May 26, 1936, H. H. Ross, $ $ ; May 24, 



1937, H. H. Ross, 1 S ; June 4, 1932, Prison 

 & Mohr, \S , 1 $ ; Aug. 24, 1936, Ross & 

 Burks, 2 $ . 



PHILOPOTAMIDAE 



Of the three North American genera be- 

 longing to this family, two have been taken 

 in Illinois, and the third occurs in Indiana 

 at a locality 17 miles from the Illinois state 

 line. 



The larvae frequent rapid streams or 

 brooks. They are very active and make 

 silken nets which form long, narrow pockets 

 shaped like a long funnel. When the net 

 is taken out of the water the whole struc- 

 ture collapses into a mass of silken folds. 



For pupation each larva constructs an 

 ovoid cocoon of small stones and debris 

 which is lined with several folds of silk. 

 This is attached on the underside of a stone 

 or other object in the water. 



The adults of Trentonius and Dolophilus 

 are secretive; those of Chimarra, slightly 

 less so. They can be collected by sweeping 

 foliage hanging over water or in humid 

 shady portions of the stream's course, espe- 

 cially during early evening. 



KEY TO GENERA 



Larvae 



1. Apex of frons markedly asymmetrical, 

 with a large or pointed left lobe and 

 a smaller right one, figs. 155, 179- 



182 Chiirarra, p. 48 



Apex of frons at most slightly asym- 

 metrical, as in fig. 156 2 



Fig. 155. — Chimarra feria larva, head. 

 Fig. 156. — Trentonius distinctus larva, head. 

 Fig, 157. — Dolophilus shawnee larva, head. 



. Frons almost perfectly symmetrical, 

 with posterior portion widened, 

 separated by a constriction from an- 

 terior portion, fig. 157 



Dolophilus, p. 45 



Frons slightly asymmetrical, without 

 constriction, posterior portion uni- 

 form in width, fig. 156 



Trentonius, p. 47 



160 '^161 



Fig. 158. — Chimarra obscura pupa, man- 

 dibles. 



Fig. 159. — Trentonius distinctus pupa, man- 

 dibles. 



Fig. 160. — Dolophilus shawnee pupa, man- 

 dibles. 



Fig. 161. — Dolophilus moestus pupa, man- 

 dibles. 



