loxg's second expedition. 227 



lowish approximate spots above the middle ; feet pale yellowish ; 

 thighs black on the basal two-thirds, those of the anterior feet 

 black only on the exterior side ; tergum with four yellow bands, 

 dilated on the sides, and gradually narrowing to the middle of 

 the back, where they are slightly interrupted, the terminal one 

 widely interrupted ; two terminal segments with large punctures 

 each side and at base ; venter with three small yellow spots each 

 side near the middle ; % with an obsolete spot each side on the 

 two segments beyond the bands, and the anus is three-spined, of 

 which the lateral ones are curved, and 9 with an obsolete, yellow- 

 ish line before the wing on each side. 



Length % three-fifths, 9 nearly seven-tenths of an inch. 

 This species is in the collection of Mr. William W. Wood. 

 The hypostoma of the male specimen is occupied by the black 

 basal spot, excepting on its anterior margin. The bands of the 

 abdomen in this species are not at all dentated. 



2. M. VENTRALIS. — Black, obscurely iridescent ; tergum [337] 

 with about five yellow bands, interrupted, but not narrowed in 

 the middle. 



Inhabits Pennsylvania. 



-J, Orbits anteriorly obsoletely tinged with dull yellowish; 

 antenna, first joint beneath yellow; hypostoma, labrum, and 

 mandibles black , palpi whitish ; thorax punctured ; a line on the 

 anterior edge, with a spot at tip on the pleura, and a small, longi- 

 tudinal, oval spot each side above the inferior wings, yellow; 

 scutel with a transverse yellow line ; metathorax at tip each side 

 compressed and yellow ; wings hyaline, very slightly tinged with 

 fuliginous ; nervures fuscous ; feet yellowish ; thighs black from 

 the base to near the knee, first pair on the anterior side only the 

 basal half black ; tergum with about five or six yellow bands, 

 which are rather wider on the back and interrupted by a very 

 narrow space; excepting the first band which is slightly undulated, 

 slightly narrowed on the back, and interrupted by a wider space ; 

 the ultimate bands narrowed each side and interrupted near a 

 spot on the lateral margin ; terminal segment with large, dense 

 punctures, as numerous on the disk as upon the sides ; anus three- 

 spined, of which the lateral ones are curved; venter each side 

 with a triangular spot at the tip of each of the dorsal bands 

 excepting the first. 



