130 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 115 



basitarsi infuscate yellow basally, apically black as in remainder of 

 tarsus. Fourth tarsal joint obcordate. Fore leg ratio 0.81; middle 

 leg ratio 0.51; bind leg ratio 0.62. 



Wings yellowish-brown by transmitted light; C extended; m-cu 

 intersects Cui near base; anal vein reaches far beyond f-Cu. Wing 

 length 2.41 mm.; venarum ratio 0.91. 



Abdomen black, with apex of each segment somewhat lighter; 

 venter yellow becoming black at segment VII. 



This identification is queried in absence of the male with its 

 diagnostic genitalia. 



Material studied: 1 female, 4 miles west of Quincy, Plumas Co., 

 July 16, 1949, W. F. Ehrhardt. 



Diamesa nivorunda (Fitch)? 



Chironomus nivorundus Fitch, Amer. Journ. Agric. Sci., vol. 5, p. 282, 1847. 

 Diamesa waltli Johannsen, New York State Mus. Bull., no. 86, p. 174, 1905, 

 not Meigen, Syst. Beschr., vol. 7, p. 13, 1838. 



Head, thorax, and abdomen entirely black except halteres, venter 

 of abdomen, and genitalia. Antennal flagellum 7-segmented; first 

 segment slightly less than two times length of segments 2 to 6 ; length 

 of segment 7 four times 6. Postoculars in single row behind eyes, 

 extending to ventral surface of head. Eyes rounded above, haiiy. 

 Palpi ratio 40:55:60:90; second segment dilated distally, then 

 narrowly constricted just before joint. 



Prothorax \vith 13 small lateral bristles; lobes completely divided 

 but with posterior margins in contact. Mesonotum strong greyish 

 pruinosity. Halteres yeUowish-white. Body length 3.80 mm. Supra- 

 alar bristles absent; prealar bristles 8, small; dorsomedial bristles 

 absent; dorsolateral bristles in single row; scuteUum with 30 to 35 

 bristles, scattered; dorsolateral bristles continuous onto shoulder with 

 only 1 bristle lateral to main line of bristles. 



Fourth tarsal segment cordiform; empodium long, with many lat- 

 eral branches; claws with 4 basal teeth that are long and attenuate; 

 comb of 17 spines; inner tibial spur long and sinuate, with heavy 

 lateral prickles one half length; outer spur slightly bent with long 

 prickles half length, ratio 44:70. 



Leg proportions: 



Wings large, anal lobe strongly right angled; C produced (0.12 mm.) ; 

 Ri dilated distally, clavate; R2+3 distinctly only on basal one-third; 



