Vol. VIII] ALDRICH-KELP-FLIES OF NORTH AMERICA 177 



black, standing out prominently, second joint about half as long as tHrd 

 arista black, penultimate segment distmct, thickened for "^^['7,^ th>rd of 

 last segment, beyond with minute, microscopic pubescence; palpi black, with 

 lonVbdstles below; proboscis short, black; back of head bulging, with a 

 few rather long hairs. . 



Thorax opaque dark gray, with an indistinct brown stripe on the acr, 

 one each side on the dc. and behind the suture a short one on the in- 

 traalars; chstotaxy as in maritima, but there are a few quite long hairs in 

 the dc rows, about the humeri, and laterally behind the suture; the hmd 

 postalar is notably long; calypters dirty, whitish, rim and fringe mdistmctly 

 brownish ; halteres rather dark yellow. , , . , , , ., 



Abdomen rather long, with parallel sides; second, third and fourth seg- 

 ments subequal, not much shorter than the first; a distinct fifth tergite 

 shows about V4 the length of the preceding one ; hypopygmm rather small, 

 its first segment with numerous smallish bristles directed backward second 

 much imbedded, when viewed from behind showing a decided no ch 

 posteriiTto the anal area; fifth sternite not in good condition in the 

 described specimen, but with long hairs on the sides; the preceding stern- 

 ites inconspicuous. ■ t ^ „a 



Legs wholly black, with long bristles ; front tibia with one in front and 

 one on outer hind side; middle tibia with one on outer front, two on 

 inner front, one on outer hind, and two on inner hind but not far out ot 

 line with the last preceding; hind tibia with three behind, four on outer 

 hTnd and four on outer front side. M^iddle femur with about four long 

 scattered bristles on lower front edge and a row on lower hmd which are 

 long near the middle, but shorter and slanting toward tip ; hind femur 

 with the usual upper outer row, and a lower outer one of about 8 long 

 Tnes beginning near base; hind femur at base below with a tuft of small 

 spfnes sifuated upon a slight elevation; hind basitarsus with a spine below. 

 Pulvilli and claws small. . , , , . , 



Wings slightly and uniformly infuscated; veins blackish, crossveins 

 not bordered; spines and setules distinct but small. 



Female : Parafacial and bucca wider (or eye smaller) ; bucca over halt 

 the eye-height, with very long bristles below; the specimen has f?"r decus- 

 sate lower frontals, instead of three as in male; abdomen without any 

 striking bristles, the second and third segments shorter than the first and 

 fourth? tibial bristles same as in male; middle and hind fem.ora as m male, 

 except that the latter lacks the spinous elevation on the base below. 

 Length iVz to 5 mm. 



One male, one female. St. Paul Island, Bering Sea, August 

 16, 1915, in the collection of the U. S. Biological Survey; the 

 Survey has a series taken at the same time and place which I 

 have not seen ; they were determined by Mr. Malloch. I have 

 seen a series of 25 specimens, taken by the Canadian Arctic 

 Expedition at Bernard Harbor, Northwest Territory, Canada ; 

 these are the property of the Canadian National Collection, and 

 were also determined by Mr. Malloch. 



Stein places some stress upon the bloodred color of the 

 halteres in both sexes, but I think it a variable character in 

 dried specimens, and it does not occur in what I have seen, 

 although they run to ariciiformis in both sexes in Stein's tables. 

 Existing descriptions say very little about the chaetotaxy. 



