68 PROCEEDINGS OF THE NATIONAL MUSEUM vol.69 



Fitch, which were taken at various Massachusetts and New Hamp- 

 shire localities. I have also seen two specimens from Illinois in the 

 collection of the University of IlUnois. 



42. BASS US DISCOLOR (Cresson) 



Microdus discolor Cresson, Canad. Ent., vol. 5, 1873, p. 52. 

 Bassus brittoni Viereck, Bull. 22, Conn. Geol. and Nat. Hist. Survey, 1917 

 (1916), pp. 227 and 229. 



Type. — The type of discolor is in the Philadelphia Academy of 

 Sciences; that of hriUoni is in the agricultural experiment station at 

 New Haven, Connecticut. 



Very similar to agilis, but much more variable in color, the thorax 

 varying from completely black to completely testaceous, and the 

 head and abdomen also varying considerably; the head is usually 

 mostly pale; and the pleura and abdomen are nearly always more 

 closely granular and more opaque than in agilis] the ovipositor 

 sheaths are a little shorter and the wings usually more uniformly and 

 more distinctly tinted with brownish. In size discolor averages con- 

 siderably smaller than agilis. 



Face at least as broad as long ; malar space about half the eye height ; 

 third segment of labial palpi minute; elevation between the antennae 

 very low, not so pronounced as in agilis; antennae usually 34 to 38 

 segmented slender, even the apical segments elongate; thorax rather 

 narrow; parapsidal furrows impressed, usually finel}^ foveolate; fur- 

 row in front of scutellum pitted; propodeum closely rugose, without 

 carinae; pro pleura entirely finely granular, with a few rugae anteri- 

 orly; mesopleura usually miimtely granular or coriaceous below and 

 with a finely foveolate longitudinal furrow; metapleura closely granu- 

 lar and opaque; hind coxae also granular and opaque; second cubital 

 cell very small, triangular, petiolate; abdomen more slender than is 

 usually true in agilis; the first tergite much longer than broad, closely 

 strongly granular and opaque; the second entirely and usully the third 

 except at apex also granular and opaque; ovipositor sheaths about 

 as long as the propodeum and abdomen combined. Head mostly 

 testaceous, with the frons vertex, and occiput usuall}'' more or less 

 black; thorax black to testaceous, all degrees of variation occurring; 

 legs testaceous; the hind femora rather broadly black at apex above; 

 the hind tibiae not paler than their femora and with a more or less 

 distinct blackish annulus near base, and the apex broadly blackish; 

 hind tarsi blackish; wings a little tinted with brown; abdomen tes- 

 taceous, more or less marked with blackish; the first tergite is some- 

 times partly blackish, and the third and following are usually more 

 or less black above, but nearly always pale laterally. Length, usually 

 3 to 4 mm. 



This characterization is chawn from the following material: The 

 types of discolor and hrittoni — six specimens in National Museum from 



