August, 1944 



Ross: Caddis Flies of Illinois 



as Psychomyia flavida, Hydropsyche bronta 

 and Neotrichia okopa. 



Of greatest interest at the park is a very 

 swift point in the river where the "leech- 

 egg" cases of the hydroptilid Leucotiichia 

 pictipes are found. These are attached at 

 the sides of 30- to 50-pound boulders in the 

 very center of the current. This is the only 

 place in the state where this species has 

 been found, and our only other nearby 

 records are considerably to the north, in 

 Wisconsin and Michigan. 



Gave Streams. — There are few caves in 

 the state which discharge a permanent flow 

 of water, and most of these have few or 

 no caddis flies of interest in the resultant 

 stream. There are two, however, which 

 produce cold, permanent streams with in- 

 teresting species: (1) At Union Spring, 

 near Alto Pass, is a small cave out of which 

 flows a stream about a foot wide ; in the 

 few feet from the cave to the bottom of the 

 hill a colony of larvae belonging to Hydro- 

 psychid Genus A occurs under the stones 

 (see p. 83). (2) Near Quincy is a cave 

 from which flows a small stream in which 



there is a large colony of Lepidostoma liba; 

 while we have found the species in two other 

 small, spring-fed streams in the state, this 

 is the only locality in which the species is 

 numerous. 



Seepage Area. — At Matanzas Lake, near 

 Havana, there is a sharp valley cut through 

 the sand ridges by a small stream. At the 

 side of this little valley, right at the base 

 of the hill, we found a seepage area a few 

 feet in diameter and not as deep as the 

 thickness of a caddis fly case. Cases of 

 Frenesia 7nissa literally covered this small 

 area, many of the larvae crawling up on the 

 leaves until the case was almost completely 

 out of the water. 



In the summer of 1941 this little spring 

 apparently dried up, for no cases were found 

 in it in October, the month in which pupa- 

 tion occurs. A few scattered individuals 

 were found in the adjacent stream, and 

 these likely represent a small reservoir of 

 population for the rehabilitation of the seep- 

 age areas after drought conditions. 



Other Peculiar Streams. — There are 

 several other streams which have caddis 



Fig. 8. — Apple River in Apple River Canyon State Park, Illinois. Outside the park this 

 stream is sluggish, muddy and has little aquatic life. The rapids inside the park, however, 

 afFord a varied caddis fly fauna, including our only record of Leucotrichia pictipes. (Photo by 

 Donald T. Ries.) 



