Dec, 1918] Nearctic Species of the Genus Laphria 153 



Laphria janus new species. 



A species which appears to have the posterior half of thorax 

 densely yellowish haired and the anterior half sparsely blackish. 

 Under the microscope, however, when the insect is viewed 

 from the front it is evident that much of the pile on anterior 

 half of thorax is golden. It is nearly erect, however, so that 

 in examining the insect from above one looks down between 

 the hairs at the dark integument of the thorax. These erect 

 hairs have black ones scattered among them. The pile on 

 posterior half of thorax is longer and more recumbent and 

 varies in color from pale yellow (sometimes almost white) to 

 bright golden. 



Beard, mystax, except for a few black hairs below, hair on coxae, and 

 pleurae pale yellowish. Hair on abdomen semi-erect, sparse and pale 

 yellow anteriorly, becoming more recumbent, dense and ferruginous 

 posteriorly. Black hair on legs (accompanied by some pale ones, and 

 the usual short, dense, rusty pile on inner side of front tibiae and tarsi), 

 vertex, occiput, neck tubercle, tuft in front of wing (sometimes yellow) 

 fringe about thorax and sparsely on anterior half as above described. 



Long yellowish to reddish hair on genitalia; anal valve moderately 

 swollen; forceps, see Figure 4. Wings brownish hyaline; center of 

 cells sometimes clear. Length, 15-20 mm. 



This form is identified in some collections as L. terrce-novce 

 Macquart, but it does not closely agree with the description.* 

 For instance, "underside of head with black hairs" and "abdo- 

 men with pale yellowish gray hairs" do not fit the present 

 species. Even if the description of terrcE-novce were a much 

 better fit, I should prefer to use a new name, since neither type 

 nor homotype are available for comparison. 



Western specimens differ slightly in general appearance 

 from eastern ones, the color of hair on abdomen averaging more 

 ardent and the tuft of hair in front of root of wing being more 

 often wholly yellow. 



Type specimen, male, and allotype, female, from near sum- 

 mit of Mt. Washington, New Hampshire, George Dimm.ock. 

 In collection of U. S. National Museum. 



Other specimens examined: Mt. Washington, N. H., 

 George Dimmock, (U. S. N. M., M. C. Z.) ; June 29, 1874; 

 H. K. Morrison, (U. S. N. M.); White Mts., N. H., George 



* Macquart, J. Dipteres exotiques, noveaux ou peu connus, 1, Part 2, 1838, 

 pp. 69-70. 



