316 



This species will in the case of the female run down to section 13 

 in my key to the species of this genus in my recently published paper 

 on the Chironomidae of Illinois*, but is readily separated from the 

 two species there given by the color. The male will run down to sec- 

 tion 8 in the same key, but may also be separated from the two species 

 with dark halteres by the color as well as several structural characters. 



The species was very common at rest on the under side of leaves 

 of trees and bushes bordering" the Sangamon River. The male bears 

 a striking resemblance to that of Probea:;ia pallida which occurred 

 along with it. 



Probezzia infuscata, n. sp. 



Female. — Head black, face, proboscis, and palpi brownish yellow; 

 basal half of antennae pale yellow, apical half fuscous. Thorax glossy 

 black, without any traces of pruinescence. Abdomen white or creamy, 

 apical half infuscated except the 2 apical segments, which are whitish. 

 Legs yellow, mid and hind coxae fuscous, apical two fifths of femora, 

 entire tibiae, and apical two tarsal joints of all legs black. Wings, 

 including the veins, whitish on basal half, apical half slightly infus- 

 cated, the veins blackish. Halteres brown, knobs black. Antennal 

 hairs pale ; thoracic setulae black. 



Eyes distinctly separated; second antennal joint rather small; basal 

 flagellar joint nearly twice as long as second, all flagellar joints con- 

 spicuously longer than their diameter, entire length of antenna about 

 one and a half times as long as head and thorax combined. Thoracic 

 dorsum smooth, setulae short and sparse; scutellar bristles short. 

 Abdomen stout, without noticeable hairs. Legs slender, femora 

 slightly swollen on apical third ; tibiae with rather noticeable setulose 

 hairs; fourth tarsal joint of all legs obcordate; fifth joint with two 

 series of ventral bristles; claws of moderate size, subequal, each with 

 short subbasal tooth. Third vein ending slightly before apex of wing, 

 first at two fifths from base of third ; cubitus forking slightly proxi- 

 mad of cross vein. 



Male. — Agrees with the female in color except that the abdomen 

 is l)lackened from the base of third segment to apex with the exception 

 of the hypopygium, which is yellowish. The wings are also less notice- 

 ably infuscated. The antennal plumes are yellowish white. 



The second antennal joint is considerably larger than in the female 

 and black in color. The fifth tarsal joint has no spines on the ventral 

 surface ; the claws are smaller and have no subbasal tooth. The third 

 vein ends at five sixths the wing length, the first beyond middle of 

 third, and cubitus forks under the cross vein. 



♦Bull. 111. State Lab. Nat. Hist., Art. 6, Vol. 10, May, 1915. 



