384 C. R. OSTEN SACKEN'S PRODROME 



a triangle in tho miilcllo, yellow ; an indistinct yellowish streak runs, on each side, from the 

 anterior margin of the segment, inside of the black, and does not reach the middle of the 

 segment ; the fifth and the following segments are black, with yellow hind margins ; 

 on the fifth the vestige of a triangle. Venter yellow ; blackish longitudinal lines on each 

 side of segments 2-4 ; the following segments black, with yellow margins. Legs ferrugi- 

 nous ; latter half of front tibiae and the front tarsi, Ijlack ; ends of the four posterior tarsi, 

 tips of hind femora and tibiae, blackish. Wings : costal and first basal cells, the latter 

 except a small hyaline square at its distal end, dark Ijrown ; the proximal end of the 

 second basal cell contains a Ijrown streak, not quite reaching tlie middle of the cell ; the 

 dark brown crossliand does not touch the hind margin, a small space at the end. of the 

 fourth posterior cell being hyaline; the fifth posterior cell (excej^t both its ends) and the 

 end of the anal cell, are also infuscated; a faint brown tinge spreads across the anal -angle ; 

 the apical spot is coalescent with the crossband, marginal and first snbmarginal cells being 

 filled out with Ijrown ; the second submarginal cell is encroached upon by a brown cloud on 

 its anterior half only ; a trace of a whitish halo on the distal margin of the crossband. 



Hah. Two female specimens, the one from Cayuga Lake, N. Y. (J. H. Comstock), the 

 other from Montreal (Wm. Cooper), agree in all the above described characters. 



This species is very like C. jnidtcus, montauns, h'daris, etc., in its general appearance and 

 somewhat in the coloring of its aljdomen ; but it is easily distinguished by the coloring of 

 its wings, as in all the above named species the first Ijasal cell is nearly hyaline and the 

 first submarginal cell contains a hyaline space, separating the brown crossband from the 

 apical spot. In C. siriahis the hyaline spot at the end of the first basal cell is much 

 smaller, the crossband stops short at the intercalary vein, the picture of the abdomen is 

 altogether dilTerent, etc. 



14. Chrysops frigidus u. sj). 



5 . The npical spot tills out the innigin:il ami first submarginal cells, ami invades a portion of the second 

 suliinargiiial ; the crossbaii'l does not reach the posterior margin, l)Ut expands toward tlie anal angle; basal 

 cells int'nseated on their proximal half; face s-liining black, with the usual strijies of yellow pollen ; r.bdomen 

 black, sides of the two basal segments yellow. 

 Length, 7-S mm. 



3 . The brown color in the basal cells occupies more space; abdomen reddish-yellow, each segment with a 

 black spot in the middle; three last segments black. 



Female. Facial callosities Ijlack, shining, prolonged anteriorly ami meeting above the 

 mouth ; between them a stripe of yellowish-gray pollen ; cheeks l:)lack, shining, separated 

 from the facitil callosities by broader stripes of the same pollen. Front clothed with grayish 

 pollen; frontal callosity and space aroinid the ocelli, black. Antennre black, the first two 

 joints more or less tinged with I'cddish ; first joint comparatively stout. Thorax blackish, 

 clothed with yellowish hairs, especitdly on the sides of the dorsum and on the plenras ; a 

 broad median greenish-gray stripe, brownish in the middle, lateral greenish-gray stripes be- 

 tween the humeri and the sctitellum ; a brown stripe between the humeri and the roots of 

 the wings ; pleune yellowish-gray, with yellow hairs and a blackish stripe in the middle. 

 Abdomen black, sides of the two first segments reddish, leaving on the second segment a 



