18 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 123 



Pachygaster wirthi^ new species 



Figures 4, 16-18 



Male. — Head (fig. 17) about as long as high; eyes large, contiguous 

 most of way from ocellar triangle to frontal triangle, upper facets 

 much larger than lower but with no sharp line of demarcation ; frontal 

 triangle distinctly and deeply depressed below level of eyes; face 

 likewise depressed but not so clearly so, concave in transverse profile; 

 postgenal area prominent, occipital orbits evanescent above; occiput 

 somewhat concave transversely above. Head black, largely shining, 

 pile yellow, that on most of occiput very short and inconspicuous, 

 black; sides of face whitish tomentose, this tomentum ending at 

 antennal bases. Antennae orange yellow, arista black to blackish. 

 Proboscis pale yellow. 



From lateral profile, anterior dorsal angle of thorax prominent; 

 scutellum approximately on plane with mesonotum, rounded, without 

 margin or notches, microdenticulate along border. Thorax black; 

 mesonotum and scutellum regularly clothed with golden tomentum, 

 which is conspicuous but by no means conceals the background ; pile 

 on pleura more whitish and largely semi-erect; large polished bare 

 areas on mesopleuron and pteropleuron. Legs yellow and yellow 

 pilose, at most base of hind coxa brownish; apical tarsomere of each 

 leg slightly brownish yellow. Wing somewhat infumated, stigma yel- 

 lowish brown; sides of discal cell almost parallel (fig. 16); part of M 

 separating basal cells feeble, its base evanescent; R2+3 arising well 

 before r-m; basal part of R 4+5 angularly bent at r-m. Microtrichia 

 lacking only at extreme base, including basal half of anal cell; alula 

 completely clothed with microtrichia. Halter yellow, knob becoming 

 whitish. 



Abdomen oval, about 1.7 as long as maximum width, widest near 

 apex of second segment; densely punctured dorsally, the punctures 

 confluent, the broad sides beyond apex of second abdominal tergum, 

 however, shining, this area extending inward somewhat along the 

 incisures and forming a complete apical margin on terga 4 and 5; the 

 polished area bearing blackish, semi-erect pile; an irregular row of 

 impressed, rounded punctures, quite distinct and much larger than 

 those of the densely punctate area, along each of the tergal incisures. 

 Venter black, shining, with scattered black pile; a large part of first 

 sternum and extreme sides of second and third with fine punctures 

 that are close together but not confluent, as on the dorsum. Genitalia 

 slender, mostly brownish to blackish; aedeagus (fig. 4) trifid, the 

 guards divergent apically; dististyli slender, acute apically. Length 

 3.0-3.5 mm. 



