1913] North American Dipterous Genus Neurigona 49 



20 Neurigona pectoralis n. sp. 



Figure 20. 



Dorsum of the thorax metalHc green; abdomen yellow with black 

 bands; front tarsi much shorter than their tibife and with the last two 

 joints flattened and fringed forming an oval tip; hypopygium black, 

 rather large. Length 4 mm. 



Male: Eyes very narrowly separated; face and palpi covered with 

 white pollen; proboscis yellow; front and occiput light metallic green, 

 the front thinly and the occiput more thickly covered with white 

 pollen; antennas yellow, arista yellowish brown; frontal bristles black, 

 orbital cilia and post-vertical bristles whitish. Dorsum of the thorax 

 light verdigris green, with yellowish pollen; pleuree black with whitish 

 pollen; humeri yellowish; scutellum yellow, with the base dark metallic 

 greenish blue; metanotum black, with white pollen. Abdomen yellow, 

 first segment more or less infuscated, second and third segments \vith 

 black bands, which are widest on the center of the dorsum, and are 

 narrowed laterally, hardly reaching the lower sides of the abdomen; 

 fourth segment with only the hind margin yellow, fifth entirely black 

 except a narrow white hind margin, interrupted on the center of the 

 dorsum, and reaching about half way to the lateral sides; hairs of the 

 abdomen mostly black on the dorsum, those on the lower part of the 

 sides pale. Hypopygium black, rather large, rounded behind, the 

 first half but little shining, appendages black or testaceous. Legs pale 

 yellow; front and middle coxee with only yellowish hairs and bristles on 

 the front side; front pair rather long, middle and hind coxae slightly 

 darkened on the outside; front tibige about one and one-fourth times as 

 long as their femora, and the front tarsi hardly as long as their femora; 

 metatarsi a little longer than the four remaining joints together, second 

 and third joints nearly equal and very slightly fiattened, fourth and 

 fifth black, flattened and fringed on each side with black hairs, forming 

 a nearly round tip to the tarsi ; front tibiae and metatarsi with a row of 

 small, hook-like bristles below; middle femora with a few black bristles 

 near the base below; middle metatarsi. about four-fifths as long as their 

 tibiae; first and second joints of the hind tarsi of nearly equal length, 

 hind tarsi shorter than their tibiee; halters, tegulae, and their cilia pale 

 yellow. Wings grayish hyaline, fourth vein ending in the apex of the 

 wing; tips of the third and fourth veins quite widely separated. 



Female : Agrees with the male, except that the hairs and bristles on 

 the front of the middle cox« are all black; the middle metatarsi are 

 hardly three-fourths as long as their tibiae, and the front tibise are about 

 the same length as their femora and much shorter than their tarsi 

 which are plane, and have the last joint blackened. 



Described from two males and two females from N. M. in the 

 National Museum collection, the two males and one female 

 were taken by H. S. Barber, at Las Vegas, N. M., Aug. 7th, 9th 

 and 13th; and the other female was taken by Townsend on the 

 White Mountains, N. M., at 6500 feet altitude. 



