298 



XX, 6 small circular spots at apices evidently indicate breathing aper- 

 tures, apical portion distinctly geniculated to the elongate base ; 2 pairs 

 of short thornlike tubercles anterior to respiratory organ, and 2 small- 

 er closely placed pairs on middle of thorax (Fig. 11) ; abdominal seg- 

 ments with distinct tubercles situated as shown in Figures 11 and 12; 

 apical segment as in Figure 13. 



Imago; Male. — Black, densely covered with gray pruinescence. 

 Head black ; antennae brown, the plumes yellow. Disc of mesonotum 

 with numerous small dark brown dots arranged as follows — a straight 

 median line of small ones, a submedian row on either side consisting of 

 irregularly placed subconfluent groups of from 2 to 4, the area on 

 which they occur broadening and the spots becoming more sparse pos- 

 teriorly ; bordering this area there is a regular line of smaller dots sim- 

 ilar to the median line, and on the lateral margins numerous slightly 

 larger dots, those near the middle being surrounded by a brownish 

 suffusion ; scutellum yellow, centrally with a broad brown mark. Ab- 

 domen dull black. Legs brown, marked with pale yellowish white 

 bands as follows — fore femora, at base, middle, and near apex, and 

 all tibia? near their bases; bases of mid and hind femora and apices of 

 all tarsi broadly pale. Wings as in Figure 2, Plate XXII. Halteres 

 brown, the apices of knobs broadly pale. 



Eyes narrowly separated, antennae with the basal joint globose, 

 only the last three joints much elongated (PI. XX, Fig. 8), entire 

 length of antenna equal to one and a fourth that of head and thorax 

 combined. The brown spots on disc of mesonotum each with a dis- 

 tinct hair; scutellum with sparse short hairs. Abdomen slender, the 

 surface hairs short and fine ; hypopygium as in Figure 6. Legs slender, 

 surface hairs on mid and hind tibise longer than on other portions; 

 basal joint of hind tarsi as long as the combined length of the remain- 

 ing joints; fourth joint about half as long as fifth; claws small, the 

 base slightly produced (PI. XX, Fig. 15). 



Female. — Differs from the male in being rather more robust, in 

 having the antennae about equal in length to the head and thorax to- 

 gether, third joint of fiagellum as in Figure 14, Plate XX. In other 

 respects as the male. 



Length, 2-2.5 ^^■ 



Illinois localities: St. Joseph, Urbana, Dubois, Ashley, Carmi, 

 Cuba, Centralia, Manchester, and Normal. All the specimens I have 

 before me were taken in April and May with the exception of one 

 male which I beat from an evergreen tree at Manchester, July 11, 1914. 



The St. Joseph record refers to a larva which the writer obtained 

 from Salt Fork and which he succeeded in rearing. The larval skin 



