52 • PROCEEDINGS OF THE NATIONAL MUSEUM vol. G9 



legs usually mostly black, but both their coxae and theu' femora 

 vary from almost entirely red to completely black; abdomen red. 

 Length, usually 3.5 to 5 mm. 



In addition to the type, which is from Connecticut, I have seen 

 two specimens in the collection of the Boston Society of Natural 

 History, from Fort Kent, Maine and Mount Gieylock, Massachusetts; 

 and the following material in the National Museum collection: Four- 

 teen specimens reared from larvae of IsopJiridis, species in flowers of 

 Rudheckia hirta, at Liberty, Texas, by L. J. Bottimer; tlu^ee from 

 Isophrictis , species in flowers of Rudbeckia maxima, at Liberty, Texas; 

 and collected specimens from Colorado; South Dakota; Georgia; 

 Leesville, Louisiana; Glen Echo, Maryland; and Harpers Ferry, 

 West Virginia. 



26. BASSOS DICOLOR (Provancher) 



Microdus bicolor Provancher, Natural. Caiiad., vol. 12, 1880, p. 179. 



Type. — In the Museum of Pubhc Instruction at Quebec, Canada. 



The close resemblance of this species to huttricki and the more 

 important differences between the two are discussed above under 

 huttricki. 



Face distinctly broader than long to the apex of clypeus; malar 

 space half, or more than half, as long as the eyes; third segment of 

 labial palpi small, but slender and distinctly longer than broad; 

 antennae of the specimens examined varying from 29 to 33 segmented; 

 parapsidal furrows very weak, smooth; a shghtly more distinct median 

 impression posteriorly on mesoscutum than is found in huttricki; fur- 

 row in front of scutellum foveolate; mesopleural furrow shallow, 

 smooth; propodeum usually riigulose and most frequently more or 

 less distinctly areolated, although sometimes the areas are not at 

 all distinctly defined; areolate of anterior wing triangular, small, 

 strongly petiolate, the petiole usually longer than the first abscissa of 

 radius; first and second abscissae of mediella about equal; first abdom- 

 inal tergite more or less striate and with two prominent dorsal longi- 

 tuainal keels extending to the apical third; tranverse impressions on 

 the second and third tergites, and the suture between the two tergites 

 usually crossed by numerous short striae; ovipositor sheaths about 

 two-thirds as long as the body, distinctly shorter than in huttricki. 

 Head black, very rarely, in exceptionally pale specimens, with the 

 face mostly ferruginous; thorax usually mostly black, but varying to 

 entirely ferruginous, the mesonotum being the first part to become 

 pale and the propodeum the last, the propodeum being \evy rarely 

 ferruginous; wings infumated; anterior and middle legs black or black- 

 ish; posterior legs black with the femora usually red or rufous; rarely, 

 in very pale specimens, the hind coxae more or less ferruginous, abdo- 

 men ferruginous, the first tergite often black basally in the darker 

 specimens. 



