466 C. R. OSTEN SACKEN'S TRODROME 



spots on each segment, gradually diminishing and becoming move rounded posteriorly ; at 

 the middle of the hind mai'gin of the segments a small fiino-e of yellowish hair, sometimes 

 assuming a subtriangular sliape. Venter yellowish, often more or less blackish, (;lothed 

 with a thin graj'ish i)ollen and yellowisli hairs. Legs yellowish red, base of femora, to a 

 greater or less extent, Ijlack ; tarsi black, except the base of the four posterior ones, which 

 is reddish ; tips of front tibii\3 blackish. Wings hyaline; crossveins and Infurcation of the 

 third vein clouded with brown ; first posterior cell broadly open. 



Male. Face dark grayish, beset with blackish hair; antenntie darker; third joint more 

 narrow ; thorax clothed with denser blackish i)ile, gray lines less distinct ; legs black, ti))ia3 

 and ])ase of four posterior tarsi reddish brown. Length, 12-lC nun., both sexes ))eing 

 rather variable in size. 



Hah. United States and British Possessions; not rare. (Massachusetts; Maine; De- 

 troit, Mich.; Illinois; (Quebec, Canada, etc.) 



I have seen AValker's T. noiaVdh in the British Museum. 



48. Tabaiius aSinis. 



Tabamis affinis Kirby, Fauna Bor.-Amcr., IV, p. 313, 1. 



Female. Eyes pidjcscent ; palpi brownish yellow, with short black hairs ; second joint 

 moderately stout at base ; face yellowish gray ; antenna) dark red, third joint black on its 

 latter half, its basal portion rather laroad, the upper angle projecting and the excision well 

 marked ; front dark yellowish gray, somewhat convergent anteriorly, clothed with black 

 hair; callosity black (seldom reddish), rather small for the size of the species, with a usually 

 spindle-shaped prolongation ; ocellar tul)ei-cle brownish IJack, very distinct. Thorax dark 

 grayish black Avith a tinge of Ijrownish, and a\ ith more or less distinct gray lines ; antealar 

 tubercles reddish. Sides of the first four abdominal segments rufous, which color leaves a 

 black stripe in the middle, narrowest on the second segment, and expanding on the third 

 and fourth (in some specimens the fourth segment is almost black, with only a roiuided 

 reddish spot on each side ; in others the red color invades even the fifth segment) ; on 

 each of the segments two to five, on the black stripe, there is a triangular whitish yellow 

 spot (formed by pollen overgrown with pubescence), the last of which, on segment five, is 

 subobsolete ; hind margins of segments yellowish, with a fringe of yellowish hairs ; better 

 preserved specimens show, on segments two and thi'ee, traces of lateral oblique yellowish 

 spots. Venter rufous, last two or three segments black. Front legs black, base of tibia3 

 reddish ; on the hind legs the end of the femora, the tibia) and tarsi are rufous ; tibiie with 

 a fringe of Ijlack liairs. Wings with a faint Ijrownish gray tinge, more marked in the cos- 

 tal cell and across the central crossveins; first posterior cell broadly open. Length, 17- 

 20 mm. 



Ilah. Northern United States and British Possessions. I have about three dozen 

 specimens from Fort Good Hope, Lake Athal)asca, Portage and Slave Lake, Lake Winnipeg, 

 Lake Superior (Michipicoten) ; Bethel, Me. ; White Mts., N. H. 



The antennaj are sometimes black, with a trace of red at the base of the third joint only. 

 The identification cannot be doubtful, as this is the largest among the allied species. 



