189S.] NATURAL SCIENCES OF PHILADELPHIA. 161 



lies when at rest, shining, ridges with five teeth-like projections, 

 posterior tibiae black, pile yellowish, base of the tibia? and tarsi red. 

 Wing hyaline, with a slight tinge of brown, veins dark brown. 

 Alula? and halteres bright yellow. 



One specimen, Sheikh Husein, October 10, 1894. 



ACROCERIDjE. 



Pterodontia Smithi n. sp. 



Length 10 mm. Head black, with yellow and brownish pile. 

 Antennse yellow. Thorax yellow thickly cover with long yellowish 

 pile, a dorsal stripe about the width of the head extends to nearly 

 opposite the base of the wings where it expands into a large dis- 

 coidal spot occupying the entire dorsal portion, a spot on the ante- 

 alar protuberance, lower portion of the pleurae and the sternum, black. 

 Scutellum yellow with brown and yellowish pile and a round central 

 black spot. Abdomen tricolor, with brown and yellowish pile ; the 

 irregular black dorsal stripe and the dark and light yellow trans- 

 verse bands that extend on either side and divide the segments into 

 two equal parts may be described as follows : The first segment is 

 covered by the scutellum and visible only on the side, is black with 

 a lateral and posterior margin of light yellow ; second, the black of 

 the dorsal stripe occupies fully one-half of the anterior and nearly 

 one-third of the posterior half of the segment, between the anterior 

 portion of the central stripes and the subtriangular black markings 

 at the anterior angles, is a small dark yellow spot representing the 

 first, dark yellow band, the light yellow posterior band extending on 

 each side of the central marking is narrowly contracted at the lateral 

 margin ; third, anterior half of the central stripe the same width as 

 the posterior half of that on the preceding segment, posterior half 

 contracted to about one-third that of the anterior portion, the black 

 lateral markings at the anterior angles quadrate, the lateral portions 

 of the light yellow band but slightly contracted ; fourth, the anterior 

 portion of the central stripe somewhat narrower at the anterior mar- 

 gin than at the middle or anterior margin of the light yellow band, 

 posterior half one-third the width of the anterior portion and not 

 quite or very narrowly touching the posterior edge of the segment, 

 lateral markings quadrate, light yellow band less contracted than on 

 the third segment; fifth segment similar to the fourth, except that 

 the central stripe does not reach the posterior margin, in one spec- 

 imen the central and lateral markings are narrowly connected, thus 

 dividing the dark and light yellow bands ; sixth segment black with 



