PROC.' ENT. SOC. WASH., VOL. 20, NO. 7, OCT., 1918 143 



Rileya compressiventris, new species. 



This species resembles mellea Ashmead in general appearance 

 but may be easily distinguished from that as well as all other 

 species by the more strongly compressed abdomen of the female 

 and the longer petiole of the abdomen in the male. 



Female. Length 2.25 mm. Funicle joints subequal and very slightly 

 broader than long, the first joint slightly the longest, head viewed from 

 ;il>ove, not more than two and one-half times as broad as long, the vertex 

 rather flat and a little more strongly sculptured than in mellea; antennae 

 inserted slightly above the lower extremity of eyes; face below eyes with 

 fine close striae which converge at clypeus; malar space a little longer 

 than base of mandible but not twice as long; without a distinct carina 

 along the malar groove and behind the eye : ocellocular line about three- 

 fourths the postocellar line; dorsum of pronotum shorter than the meso- 

 scutum; mesoscutum and scutellum rather strongly scaly-punctate; pro- 

 podeum with a distinct straight transverse carina, the surface in front of 

 this carina as well as behind longitudinally striate, the median stria a 

 little stronger than the others; stigmal vein about half the length of po.st- 

 marginal and a little more than one-third the length of marginal ; abdo- 

 men about equal in length to the head and thorax, strongly compressed 

 from the sides, its dorsal width much less than its dorso-ventral height, 

 the dorsum strongly arched antero-posteriorly; tergites, except the three 

 basal ones, finely sculptured; first tergite (not counting the very short 

 petiole) longer than broad, elliptical in outline; exposed apex of second a 

 little less than half the length of first and about equal to half the exposed 

 length of third, the latter reaching to about the basal one-third of abdo- 

 men; fourth tergite covering most of the remainder of abdomen; fifth 

 about equal to the second; following tergites very short; tip only of the 

 ovipositor exposed. Color pale reddish testaceous, the head except v rtex 

 pale yellow, antennal flagellum brownish, apex of ovipositor sheaths and 

 tarsal claws black. 



Mule. Length 2 mm. Agrees with the female except that the funicle 

 joints arc subquadrate, the abdominal petiole is slender, a little more 

 than twice as long as thick, and finely sculptured; the abdomen is not 

 strongly compressed, its tergites differently proportioned and the pos- 

 terior tibiae are dark brown or blackish cxrept at base; the fii>t tergite 

 (excluding the petiole) is nearly circular in outline, the second very nar- 

 rowly exposed, third twice as long as the second, the three basal tergia-s 

 together covering about one-fourth of the abdomen; fourth tergite cover- 

 ing the greater part of abdomen; fifth about as long as the first ; following 

 tergites practically concealed from above. 



