242 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



Larva. — Fig. 811. Length 7 mm. Head 

 brown with spots of a lighter shade scat- 

 tered over the entire surface. Pronotum 

 and legs straw color, the pronotum finely 

 speckled with light brown. Labrum with 



Fig. 833. — Oecetis cinerascens, case. 



hairs forming an irregular band across 

 apical third, first abdominal segment with 

 dorsal holding process large and without 

 setae. 



Case. — Fig. 833. Length 8-10 mm., con- 

 structed of bits of stems and other debris 

 into a somewhat irregular log-cabin case. 



Adults. — Length 11-13 mm. Color me- 

 dium shades of brown; in life somewhat 

 hoary due to the pale hair; the wing mem- 

 brane with several dark spots situated at 

 the vein forks. Male genitalia, fig. 822: 

 tenth tergite consisting of a single stylelike 

 projection; cerci fairly long and parallel 

 sided, apex rounded ; claspers with a wide 

 basal portion which tapers suddenly to a 

 long apical curved filament; aedeagus fairly 

 long, the apex produced into a projecting 

 beak. Female genitalia, fig. 827, with ninth 

 sternite large and almost circular, deline- 

 ated by very distinct arcuate lines, the apical 

 portion of the sternite composed of a pair 

 of concave sclerites; bursa copulatrix simple. 



The common log-cabin case of this species 

 is one of the most abundant features of 

 many lakes and streams scattered through- 

 out the state. The species is frequently 



taken in great numbers and occurs on the 

 wing from May to late September, with a 

 constant cycle of generations. 



This species is widely distributed through 

 the Northeast, and occurs south to Georgia, 

 southwest through the Ozarks to Texas, 

 and northwest to Saskatchewan. We have 

 records from Arkansas, Georgia, Illinois, 

 Maine, Massachusetts, Michigan, Minne- 

 sota, Missouri, New Brunswick, New York, 

 Nova Scotia, Ohio, Oklahoma, Ontario, 

 Pennsylvania, Quebec, Saskatchewan, South 

 Dakota, Tennessee, Texas, Virginia and 

 Wisconsin. 



Illinois Records. — Many males and fe- 

 males and 1 pupa, taken May 7 to Septem- 

 ber 25, and many larvae and nine cases, 

 taken April 15 to October 17, are from 

 Algonquin, Antioch, Beardstown (Mus- 

 cooten Bay), East Fox Lake, Elgin (Botan- 

 ical Gardens), Fox Lake, Grass Lake, 

 Havana (Quiver Lake, Thompson's Lake, 

 Illinois River), Henry, Herod, Homer, 

 Johnsburg (Fox River), Liverpool, Mc- 

 Henry, Meredosia, Milan, Momence, 

 Mount Zion (Fork Lake), New Memphis 

 (Kaskaskia River), Olive Branch (Horse 

 Shoe Lake), Peoria, Pistakee Lake, Put- 

 nam (Lake Senachwine), Quincy (Willow 

 Slough), Richmond, Rosecrans (Des Plaines 

 River), Round Prairie, Savanna (Missis- 

 sippi River), Springfield (Sangamon River), 

 Spring Grove, Stewart Lake, Urbana 

 (Crystal Lake), Wilmington, Wood River, 

 Zion (Dead River). • 



Oecetis inconspicua (Walker) 



Leptocerus inconspicuus Walker (1852, p. 

 71); cf. 



Setodes sagitta Hagen (1861, p. 284); c?. 

 Setodes micans Hagen (1861, p. 283); cf, 9. 

 Setodes flaveolata Hagen (1861, p. 282); 9. 

 Oecetina parvula Banks (1899, p. 215); 9. 

 Oecetina flavida Banks (1899, p. 216); cf, 9. 

 Oecetina floridana Banks (1899, p. 216); d^. 

 Oecetina apicalis Banks (1907rt, p. 129); cf. 

 Oecetina inornata Banks (1907^, p. 128); 9. 



Larva. — Fig. 834. Length 8 mm. Scle- 

 rotized parts straw color to pale yellowish 

 brown, the head varying from an almost 

 immaculate condition to a distinct dark 

 brown pattern as in fig. 834. First segment 

 of abdomen with dorsal hump large and 

 without setae. 



Case. — Length 9 mm." Constructed of 

 stones and sand grains, frequently irregular 



