7 



veins suong, black, a thickening in the first vein where it reaches the 

 costa ; third and fourth veins subparallel, the fourth vein ends sh'ghtly 

 before the tip ; posterior cross-vein bowed outwardly, perpendicular to 

 the last segment of the fourth vein, a slight lobe under the posterior 

 cross-vein ; anal angle full, rounded. Halteres and tegulje yellow ; 

 tegular cilia black. 



One specimen; Chicago, Illinois, June lo, 1899; collected by 

 Dr. Wm. AI. Wheeler. 

 6. Pelastoncurus Wheeler ii, n. sp. (Fig. 15.) 



Male. — Length 3.75 mm., of wing 3 mm. Face of moderate width, 

 narrowest in middle, green, thickly overlaid with silvery dust, becoming 

 yellow toward antennae. Proboscis piceous, palpi silvery, with a few 

 hairs. Antenna? wholly reddish-yellovv^, slightly subfuscated at apex ; 

 third joint short, ovate, bluntly pointed, arista short, tapering, with strong 

 plumosity. Vertex largely green, dusted with yellowish-brown, on each 

 side of ocelli a bluish space. Post-ocular cilia black above, white below; 

 a i&'N post-oral bristles present. Thoracic dorsum when viewed from the 

 front dusted with yellowish brown, wholly green except a purplish line on 

 outer side of acrostichals, gradually wider behind, where it covers the dor- 

 sum except a pre-scutellar, triangular green spot. Above the base of the 

 wing a ^--shaped black velvety spot extends forward, terminating above 

 in a silvery spot visible only from above. Scutellum green, with brown- 

 ish dust, glabrous. Abdomen green, broadly silvered at sides, toward 

 base of each segment cupreous ; incisures blackened ; first segment later- 

 ally with a strongly-marked marginal row of erect black bristles. Hypo- 

 pygium subpedunculate, rather slender, dorsal half obliquely marked 

 with green, glaucous, apical half ( = remainder) shining, translucent 

 yellow, internal appendages fuscous, enlarged, appearing like a second 

 set of lamellae ; at base of these is a close fringe of yellow bristles ; penis 

 not projecting ; lamelhe yellow, rather small, bent backward, circular at 

 tip, fringed with light straggling hairs. Pleura concolorous with sides of 

 abdomen. Fore coxae pale yellow, silvery in front, and with a moderate 

 coating of black hairs ; middle and hind coxae glaucous basally on outer 

 face ; middle coxae with several black bristles anteriorly and hind coxce 

 with its usual bristle on outer side. Legs wliolly yellow except toward 

 tip of tarsi, where infuscation commences ; metatarsus of fore legs shorter 

 than three joints following, of middle legs shorter than two following, and 

 of hind legs shorter than next joint; hind femora with a strong bristle on 



