1913] North American Dipterous Genus Neurigona 45 



17 Neurigona arcuata n. sp. 



Figure 17. 



Thorax greenish; abdomen yellow, with black bands; hypopygium 

 small black; wings with the costa much arcuated, and with a brown 

 cloud along the front; front tarsi with the fourth and fifth joints black, 

 the fifth joint nearly at right angles to the fourth. Length of male, 3^ 

 mm. ; of female, 3 ^-3 ^^4 nim. 



Male : Face silvery white, not very narrow for a male, but somewhat 

 narrowed in the middle; proboscis yellow; front and occiput greenish, 

 thickly covered with white pollen; frontal bristles black, orbital cilia 

 whitish; antennas yellow, arista brownish. Mesonotum metallic green, 

 somewhat shining but dulled with grayish pollen, the narrow space 

 between the acrostichal bristles more shining and without pollen ; humeri 

 and posterior angles of the dorsimi yellow; pleurse black, thickly cov- 

 ered with white pollen; scutellum yellow; metanotum black, a little 

 shining, and with white pollen. Abdomen yellow, dorsum of segments 

 two to four with wide black bands; the fifth segment has a narrow 

 black band; hairs of the abdomen mostly yellow, including the long 

 bristles on the hind margin of the first segment; hypopygium small, 

 black or testaceous, polished, appendages lighter testaceous, or sordid 

 yellow. Legs pale yellow, front coxas bare with a few yellow bristles 

 near the tip; middle coxae with black hairs and bristles; front femora 

 with a few long yellow hairs near the tip on the outside; fourth joint of 

 front tarsi not much more than one-half as long as third, shorter than 

 fifth, and with a few long black hairs at tip, fifth joint and most of fourth 

 black, fifth joint nearly at right angles to fourth; front metatarsi fully 

 three-fourths as long as their tibise; middle tarsi with the second, third, 

 and fourth joints slightly flattened, becoming black from the middle of 

 the second joint, and with the metatarsi nearly as long as their tibiae; 

 middle tibiae more or less infuscated in the center; first and second 

 joints of the hind tarsi about equal. Tegulae and their cilia pale yellow. 

 Wings with the costa much arcuated ; posterior margin indented at the 

 apex of the fifth vein ; third vein curved backwards towards the fourth ; 

 last section of the fourth vein curved forwards from a little beyond the 

 middle in such a manner as to be nearly parallel with the third at tip; 

 a brown cloud along the front of the wing, from about the tip of the 

 first vein to the tip of the third, fading out back of third vein, and widest 

 in the middle; veins brown, yellow at the base of the wing. 



Female: Agrees with the male except in the following points; all the 

 tarsi becoine fuscous from the middle of the second joint; front femora 

 have no long hairs at tip ; wings with the costa less arcuated, and with- 

 out distinct cloud, but the front of the wing is slightly tinged with 

 yellowish brown; the middle tarsi slightly flattened as in the male but 

 less so; front tarsi plain; second joint of the hind tarsi longer than 

 the first. 



Described from five specimens taken by me at Kearney, 

 Ont., July 3, 1909; and many specimens taken in the vicinity 

 of Buffalo, N. Y., June 6th to July 4th. 



