276 NEW YORK STATE MUSEUM 



Genus chironomus 



Meigen, 1803 



The following table contains North American species which are 

 not included in the key given in Bui. 86, and in addition tabulates 

 the males of those species which are characterized by their dusky 

 thorax and abdomen (the thorax sometimes having yellow humeri 

 and faint indications of paler division lines upon the dorsum, the 

 segments of the abdomen sometimes with gray or yellowish posterior 

 margins; legs nearly unicolored, yellowish to blackish). 



a Wings with several spots or bars 

 h Wings with several spots 



c Tibiae each with two distinct white bands n a e v u s Mitchell '08 



cc Tibiae without distinct white bands 

 d Length 2 mm. or less 



e Wings with several spots, one at the cross vein : 



labeculosus Mitchell '08 

 ee Spot distad of cross vein, halteres pale, foremetatarsus i^ times 



as long as the tibia n e e d h a m i i n. sp. 



dd Length over 2.5 mm., halteres with dusky tip, foremetatarsus nearly 



i^ times as long as the tibia nubeculosus 



hh Wings with fasciae or bars 



c Wing with two complete brown bars, the distal one mottled with clear 



spots perpulcher Mitchell '08 



cc No clear spots on bars 



d Legs nearly wholly whitish, knees slightly brownish, less than one 

 fourth of tibia brownish 



e Wing without black apical band calopterus Mitchell '08 



cc Wing with wide apical band zonopterus Mitchell 'c8 



dd Apex of each femur and basal fourth (or more) of each tibia, 

 blackish 

 e The dark band at apex of wing measured along i?2-j-5 less than 



half as wide as the white band which precedes it 



poecilopterus Mitchell, *o8 

 ce The width of the apical band nearly equal or greater than the 

 white band which precedes it 

 / Entire fore and hind tibiae dark, .n ephopterus Mitchell, 'c8 

 // Fore tibiae not wholly dark 



g Apical half of hind tibiae white. pulchripennis 



gg Apex of hind tibiae dusky 



h Middle section of hind tibiae white 



e X q u i s i t u s Mitchell, '08 



hh Middle section of hind tibiae not pure white 



t a e n i a p e n n i s 

 aa Wings unspotted, somclinics with darkened cross vein 



b Thoracic stripes gray or blackish, or thorax wholly dull black ; abdomen 

 mainly black 



