126 ENTOMOLOGICAL NEWS. [April, 



■sum, and a cross-band on the third segment behind its middle, blacl:. Legs 

 yellow, apices of femora brown. Wings yellowish hyaline. Length 12 mm. 



Washington. Received from Prof. O. B. Johnson, after whom 

 the species is named. Differs from all the previously described 

 •species by its translucent, yellow scutellum. The head resembles 

 Figure 7, Plate IX, of Williston's "Synopsis of the North 

 American Syrphidse," but the facial tubercle is larger, and the 

 underside of the head is more nearly horizontal; the venation is 

 similar to figure 3 of the .same plate, except that the third vein 

 is straighter and its last section longer. The thorax and scutellum 

 are destitute of long, stout bristles. 



Geroplatas fasciola n. sp. 9 • — Head, including the greatly flattened 

 antennae and large palpi, dark brown, the retracted proboscis, base of 

 third antennaL joint, and a small spot beneath each antenna, yellow. 

 Thorax shining brown, a medio-dorsal vitta on the posterior half, and the 

 lateral margins, yellow; pleura yellow, a large spot above the middle 

 co.Xce and small one above the hind coxse, dark brown. Scutellum yellow, 

 its base brown; center of metanotum dark brown. Abdomen shining 

 blackish brown, base of each segment, except the first, yellow; on the 

 second, third and fourth segments prolonged posteriorly as an indistinct 

 dorsal vitta; coxae and femora yellow, bases of middle and hind femora 

 and of hind coxae, blackish brown, tibiae and tarsi b/ownish-yellow. 

 Wings pale yellowish, the apex between tip of first vein and of anterior 

 branch of the fifth blackish, apex of anterior branch of fifth vein bordered 

 with blackish, this color projecting into the fourth posterior cell near its 

 middle; apex of auxiliary vein far beyond the origin of the third, being 

 opposite the origin of the fourth; subcostal cross-vein before the middle 

 of the distance between humeral cross-vein and tip of this auxiliary vem; 

 anterior branch of third vein very oblique, ending in costa beyond apex 

 of first vein. Knob of halteres black. Length lo mm. 



Washington. Received from Prof O. B. Johnson. The only 

 •other described North American species ( carbonarhcs ) has a 

 wholly black thorax, and a black abdomen margined with w hite. 



STUDIES AMONG THE FOSSORIAL HYMENOPTERA.-II. 



Synopsis of the N. Am. species of the genus Didineis Wesmael. 



By William J. Fox. 



DIDINEIS Wesm. 

 Didineis \^&sm., Revue Critique, p. 96, 1851. 

 Alyson Cresson, Synopsis, p. 117, 1887. 



This genus resembles Alyson in many respects, but can be at 



