362 APPENDIX. 



middle of the hypostoma nearly to its tip ; the rufous colour 

 on the basal joints of the antennae is obsolete ; labrum black 

 on the disk ; mandibles black, excepting a small, rufous 

 spot at base ; the three last bands of the tergum are desti- 

 tute of any rufous colour about them ; venter densely co- 

 vered with hair ; inandibles, as in the male, three-toothed ; 

 posterior coxae unarmed. 



Length about the same as the male, but more robust. 



2. M. emarginata. Black ; a band on each abdominal 

 segment, slightly interrupted in the middle, and emargin- 

 ated each side before. 



Inhabits Missouri. 



9 Body punctured, above glabrous ; head with a small 

 yellow dot each side of the vertex ; mandibles five-tooth- 

 ed ; thorax with a small, whitish spot before the wings ; 

 wing-scale whitish, with a brown spot ; a whitish spot on 

 the posterior angles, forming a curve with two whitish 

 spots on the scutel ; icings hyaline, nervures fuscous ; /eet 

 black, a dilated whitish line on the exterior side of the 

 tibia, tarsi with dull yellowish hair ; tergum convex, a 

 whitish band on each segment, very slightly interrupted 

 in the middle, and, excepting the first one, deeply emar- 

 ginated each side before, the terminal segment with two 

 rounded spots instead of a band. 



Length less than seven-twentieths of an inch. 



3. M. Jiigatoria. Black ; a band on each abdominal seg- 

 ment, interrupted in the middle and entire each side. 



Inhabits Missouri. 



9 Body punctured, above nearly glabrous ; head with a 

 yellow line on the superior part of the cheeks ; hypostoma 

 with a dilated, yellow line, which extends upon the ante- 

 rior orbits nearly to their summit ; thorax with a widely in- 

 terrrupted line before, extending round above the wings. 



