BY FRANK H. TAYLOR. 809 



Described from two specimens. Allied to S. boi'ealis mihi, but 

 it is a more slender species. For other differences, see under 

 that species. Cotype in Coll. Hill. 



SiLVIUS BOREALIS, Sp.n. 



9. Length, 10"25; width of head, 4; width of front at vertex, 

 0*5; length of wing, 9*5 ram. 



Head grey, clothed with grey hairs, basioccipital region very 

 pale ochraceous; eyes with inner margins parallel, the upper 

 third dull black, lower two-thirds with three, horizontal rows of 

 dull fiery-red, and two of pale purplish-blue, the rows alternating: 

 front rusty-brown, the edges grey; frontal callus irregularly 

 triangular, shining-black, tumid, apex drawn out to a point, and 

 terminating about the middle of the front; ocelli shining-black, 

 conspicuous; subcallus pale ochraceous, first segment of antennae 

 dusky-brown, swollen, clothed with scattered, semi-erect, black 

 hairs, second and third segments pale vandyke-brown, the former 

 very short, with a few, scattered, black, semi-erect hairs, base of 

 the latter broadly triangular; palpi yellowish, tips brown, trun- 

 cate, slender, about two-thirds the length of the proboscis, the 

 latter black. 



Thorax dull reddish-brown, with a faint, black, median, longi- 

 tudinal stripe, clothed with mixed grey and dusky hairs, lateral 

 margins clothed with moderately long, dusky hairs in front of 

 the wings; scutellum similar to the thorax, but with the apical 

 half brighter reddish-brown; pleurse and pectus dusky, the former 

 tinged with brown on the upper margins. 



Abdomen reddish-brown, becoming darker towards the apex, 

 densely clothed with semi-erect, black hairs; venter reddish- 

 brown, clothed with scanty, pale hairs on the apices of the 

 segments. 



Wings moderately broad and elongate, veins on apical half of 

 wing black, paler on the basal half, anterior branch of the third, 

 longitudinal vein with a short appendix; stigma elongate, narrow, 

 inconspicuous, pale yellow; squamae with a faint, yellowish tinge; 

 halteres mummy-brown, knobs creamy. 



