1977] 
Porter — Mesostenines 
57 
Tyloids carinate but either obsolescent and almost impossible 
to see or, if fine and sharp, generally shorter than the length 
of their segments; lower metapleuron with fine, weak punc- 
tures 7 
6. Malar space 0.75 as long as basal width of mandible; clypeus 
moderately convex in profile; mesosternum usually entirely 
fulvous, sometimes partly black and rarely entirely black; 
epomia rather weak 22. D. acadia Cushman 
Malar space 0.83 as long as basal width of mandible; clypeus 
weakly convex in profile; mesosternum largely or entirely 
black; epomia moderately strong D. rugosa Townes 
7. Mesoscutum black with a pair of median white lines or with 
a median white blotch 8 
Mesoscutum mostly or entirely fulvous, with or without a pair 
of median whitish dashes 10 
8. Tyloids sharp longitudinal carinae on 4 segments but in most 
cases shorter than their segments; flagellum with a white 
band on about 5 segments; pronotum apicad of basal trans- 
carina white with a broad black stripe along pleural carina 
almost to apex and black narrowly along basal trans-carina 
D. rufigaster Cushman 
Tyloids hard to see, low, indistinct ridges extending about 0.3 
the length of several segments; flagellum at most with a 
poorly defined postmedian brown section; propodeum api- 
cad of basal trans-carina dull fulvous to yellowish or whitish 
and without black or with black only along basal trans- 
carina 9 
9. White orbital ring interrupted on vertex and upper half of 
temple; pronotum white with a very large black apico-lateral 
area; mesopleuron black with white on subalarum and spec- 
ulum and with more or less whitish stained fulvous on most 
of lower 1/3 of mesepisternum behind prepectal carina as 
well as throughout on mesepimeron .17. D. sphenos n. sp. 
White orbital ring complete; pronotum wholly white; meso- 
pleuron mostly whitish or stramineous to weakly brownish 
white, in some specimens with black on as much as anterior 
1/3-1/ 2 below sub-alarum 16. D. macula (Cameron) 
