Oct., '08] ENTOMOLOGICAL NEWS. 375 



Posterior face of metathorax without a pale spot on each side, or with 

 a very small one ; spot on pleura small or wanting ; no lines 

 on the mesonotum monodonta. 



2. Venter black, except a small spot on each side of second and third 



segments ; band on first abdominal segment dentate in mid- 

 dle ; markings greenish or pale yellowish. 



monodonta neomexicana. 

 Venter with much more yellow 3. 



3. Mandibles black ; scape entirely black ; pectus not margined with 



yellow monodonta deltaensis. 



Mandibles yellow ; scape in front yellow ; pectus margined with yel- 

 low monodonta argentifrons. 



Microbembex monodonta monodonta Say. 



This subspecies seems to be eastern. The female described 

 by Pattern (p. 362, v, Bull. U. S. Geol. Survey) was from 

 Connecticut. We have a male and female from New Jersey. 

 The mark on the pleura is wanting in both of these. Patton 

 (loc. cit. , p. 363) describes the specimens from Kansas as dif- 

 fering from the eastern ones in much the same way as ocddcn- 

 talis differs from monodonta. 



Microbembex monodonta occidentalis subsp. n. 

 The characters in the above table will separate this subspe- 

 cies from monodonta monodonta its nearest ally. The markings 

 in all the specimens before us are greenish. The silvery pile 

 is usually quite dense. We have specimens from Paris, Tex. 

 (C. R. Jones), and Colo. 



Microbembex monodonta neomexicana subsp. n. 



This subspecies seems quite distinct. The dentation of the 

 first abdominal band, the mostly black venter, the yellow cly- 

 peus and labrum make it easily recognized. The markings 

 vary from greenish-white to pale yellow. On the average it 

 is smaller than the two preceding subspecies. Many speci- 

 mens from Las Cruces New Mexico, August 3Oth, at flowers 

 of Solidago canadensis (C. H. T. Townsend). 



Microbembex monodonta deltaensis subsp. n. 



The table will separate this from the other subspecies. The 

 markings are lemon-yellow. The sides of the venter beyond 

 the second segment, and the second ventral segment except 



