1913] North American Dipterous Genius Neurigona 39 



10 Neurigona floridula var. infuscata n. var. 

 Figure 10. 



Thorax and abdomen yellow, the latter with more or less distinct 

 bands; hypopygium black, more or less yellow on the first half; front 

 tarsi plain, and with the fourth joint more than one-half as long as the 

 third; tip of the wing infuscatad. Length, 5^ mm. 



Male: Face rather wide for a male, somewhat narrowed in the 

 middle, silvery white; antennae yellow; front and occiput black, covered 

 with white pollen; orbital cilia and post- vertical bristles yellowish 

 white. Thorax yellow, shining on the dorsum; flattened space before 

 the scutellum dull with yellowish pollen; pleurae paler and covered 

 with white pollen, a black line in front of the halters, also a black spot 

 in front of the middle coxae; metanotum yellow, more or less infuscated 

 close to the abdomen; scutellum yellow, paler below. Abdomen yellow, 

 the first segment paler and more or less infuscated at base; second and 

 sometimes the third segment with a distinct black band at base; fourth 

 segment more or less infuscated, but hardly banded; sometimes the 

 third and fourth segments almost entirely yellow; venter yellow, with a 

 transverse black line at hind margin of third segment, this line fringed 

 with long yellowish hairs; hairs on the dorsum of the second, third, and 

 fourth segments black, except on the lower edges where they are more 

 yellowish. Hypopygium black, shining, and testaceous or yellowish on 

 the first half. Legs pale yellow; front coxas with yellow hairs on the 

 front side, and black bristles near the tip; hairs and bristles of the mid- 

 dle cox« black; a black bristle on each middle and hind trochanter; a 

 few yellowish hair-like bristles at base of middle femora below; one or 

 two yellowish bristles above front coxae ; front tarsi hardh^ twice as long 

 as their tibiae, the first joint about the same length as the remaining four 

 joints together; fourth joint less than one-half as long as the third; 

 fifth joint black; middle metatarsi the same length as their tibiae; first 

 joint of hind tarsi shorter than the second; middle and hind tarsi infus- 

 cated almost from the base. V/ings hyaline, strongly tinged with brown 

 along the front, and with a distinct cloud at tip; last section of fourth 

 vein bent forward at the middle and ending in the apex of the wing, not 

 far from the tip of the third vein; anal angle obsolete; veins yellowish 

 brown to brown. 



Female: Differs from the male in the form of the wings, the anal 

 angle being well developed; wings a little less tinged with brown in 

 front, and without the cloud at tip. Abdomen without distinct bands, 

 but sometimes darkened in spots. 



Described from thirteen males, which I took at Little Val- 

 ley, N. Y., June 10, 1912; and twenty females from Pa., R. I., 

 Mass., N. Y., N. J., Mich., and Wis. 



This may be a distinct species, but I cannot find any struc- 

 tural character to separate it from floridula. Both sexes are a 

 little larger and more robust than the specimens of floridula 



