160 



PROCEEDINGS OF THE ACADEMY OF 



[1898. 



Posterior femora greatly thickened, outer portion on the under 

 side, armed with two ridges having teeth-like projections (Fig. 1) in 

 the groove between these ridges, the tibia lies when the fly is at rest, 

 posterior tibiae arcuated and the outer half thickened, first joint of 

 the posterior tarsi dilated and as long as all the other joints. Wings 

 as shown in Fig. 2. Type M. sexfasciatus. 



Megatrigon sexfasciatus n. sp. 



9 . — Length 9 mm. Face, front and vertex granulose, (except a 

 narrow longitudinal space on the front,) black, shining, with long 

 whitish pile on the face and front yellowish on the vertex, mouth 

 parts reddish, the two upper ocelli showing a red metallic lustre 

 in certain light; posterior and inferior orbits with a dense yellow 

 pubescence, eyes sparsely covered with white hairs. Antennae 

 and arista? black, base of the aristae and second joint of the antennae 

 reddish. Thorax black, shining, granulose, with 

 yellowish-white pile, humeri reddish, a dense yellow 

 pubescence forms three dorsal stripes, and a continuous 

 margin extending from the anterior end of the outer 

 dorsal stripes, the latter only reach the suture, while 

 the middle stripe almost reaches the posterior margin, 

 pleurae with a dense yellowish pubescence and long 

 whitish pile, posterior angle reddish with bright 

 1- yellow pile, scutellum black with a yellow posterior 

 margin and long yellowish-white pile. Abdomen convex, black, 

 granulose, with sparse yellowish-white pile and six transverse bands 

 of dense yellowish pubescence arranged as follows: An arcuate 

 band on the second segment extends from the posterior angles to 

 the middle where it is very narrowly interrupted ; third, with a basal 

 and a slightly arcuated middle band; fourth 

 with a basal, middle, and posterior band, the 

 middle one slightly curved, lateral margins 

 of the third and fourth segments yellow, pos- 

 terior part of the first segments shining and 

 the posterior margin of the fifth yellow. 

 Venter concave, brown with dense grayish pubescence and sparse 

 white pile, lateral margins blackish. Femora black, with long whit- 

 ish hairs, coxae brown, anterior and middle tibiae and tarsi red 

 covered with yellowish hairs, under side of the tibiae near the outer 

 end with a brownish band. Groove on the under side of the outer 

 portion of the posterior femur into which the basal half of the tibia 



