112 DIPTERA OP NORTH AMERICA. [PART III. 



Almost chocolate-brown, with a grayish pollen ; thoracic dorsum with six 

 black spots before the suture and with two beyond it, to which are 

 added on each side two very small dots. Long. corp. 0.32 ; long. al. 

 0.37. 

 Syic. Diacrita costalis Gerst. Stett. Ent. Zeitschr. xxi, p. 197. Tab. II. 



Almost chocolate-brown, covered with a whitish-gray pollen 

 and opaque. Head dark-yellow, the upper part of the occiput 

 generally brownish-yellow; the broad front, in the vicinity of the 

 ocelli and in front of these, more reddish-yellow ; on both sides, 

 near the orbit, there is a rather large, shallow impression, covered 

 with white pollen ; on the anterior end of the front there is a 

 small triangular spot, covered with snow-white pollen. Imme- 

 diately below each of these spots, upon the face, there is a velvet- 

 black round spot, contiguous with the orbit, and immediately 

 below the latter a spot covered with snow-white pollen. The 

 upper part of the face, which is carinate and retreating, has, on 

 each side, a transverse spot, clothed with white pollen. In the 

 same way, the posterior orbit of the eyes has a pollinose white 

 border, which also extends over the cheeks in the shape of a 

 stripe. The antennae are almost ochre-yellow, their third joint 

 elongated-oval ; the basal joint of the arista is so short as to be 

 almost imperceptible; the second joint is comparatively long, both 

 dark ochre-yellow ; the third joint is blackish, with the exception 

 of its extreme basis ; in the vicinity of the basis, it is as stout as 

 the first two joints, more attenuated afterwards, and clothed with 

 an extremely short pubescence. The humeral callosities are 

 brownish-yellow, and rather shining ; thoracic dorsum marked 

 with moderately large, rounded-oval, brownish-black spots ; before 

 the region of the transverse suture there are six of them, arranged 

 in two regular transverse rows; beyond this region there are 

 two approximated spots, the interval of which is equal to that 

 between the spots of the first two rows; moreover, behind the 

 region of the suture, on each side, may be noticed two very small, 

 almost punctiform dots, placed one behind the other ; of these, 

 the anterior one is situated before, the posterior one at an equal 

 distance behind the last two of the larger spots. The coloring 

 of the convex scutellum, which is beset with four, not very long 

 bristles, approaches the chestnut-red. The feet are concolorous 

 with the remainder of the body ; an admixture of yellow is per- 

 ceptible on the first joint of the tarsi only. Halteres whitish- 



