532 



dominal segment with band of strong setulae on posterior margin con- 

 sisting of three transverse series, and a less distinct transverse band 

 of about the same width on disc of segment, separated from the pos- 

 terior band by a clear space which is about ecjual in width to the band 

 itself, disc anterior to the preapical band with very weak setulse which 

 are only visible under a high magnification ; segments 3-5 with the 

 greater part of the disc covered with setulae except near the anterior 

 margin, and on several oval areas, two or three of which are most 

 conspicuous near the posterior margin, where the setuUe become 

 rather stronger, and slightly in front of the posterior margin there is 

 a bare transverse strip, and on the posterior margin a transverse band 

 of very weak setula; which are more numerous than those on second 

 segment ; sixth segment similar to fifth except that the setulse are 

 strongest on middle of disc instead of near posterior margin and that 

 there is a rather noticeable group near the postero-lateral angle ; each 

 setulose segment with several weak hairs, four of which, the most dis- 

 tinct, being widely separated and forming a transverse line near pos- 

 terior margin; lateral margin of each segment with a single weak hair 

 near middle and another near apex which are not flattened as in other 

 species. In other respects similar to nivoriundus. 



Illinois localitv, Thompson's Lake, near Havana, April 27, 19 14 

 (C. A. Hart and j. R. Malloch). 



Orthocladius sp. E 



Larva. — This species very closely resembles species C, except that 

 the central pale portion of the labium is simple (PI. XXIX, Fig. 17). 



Illinois localities : Illinois River at Spring Valley, Starved Rock, 

 De Pue, and Marseilles ; and Spoon River. 



Gexus incertus a 



Several larval specimens in the collection of the State Laboratory 

 belong to a genus which I can not definitely identify without reared 

 material. It is possible that they belong either to Cricotopus or to Or- 

 thocladiiis, sens. lat. 



Larva. — Length, 3.5-4.5 mm. Greenish. Head nearly twice as 

 long as broad; eye spots separated by a short interval or confluent; 

 antenna slightly longer than mandible, basal joint more than three 

 times as long as its diameter, second joint about one third the length 

 of basal and nearly as long as the next three joints taken together; 

 mandibles with 2 very poorly defined teeth ( PI. XXX, Fig. i ) ; labial 

 plate rather variable in form, generally as in Figure 15, Plate XXIX, 



