356 PROCEEDINGS OF THE ACADEMY OF [1895. 



MALES. 



Labrum basally with a distinct, transverse impression 2 



Labrum not impressed basally 8 



2. Clypeus entirely or in greater part black; sixth dorsal segment 



spotted Belfragei. 



Clypeus entirely yellow; sixth dorsal segment rarely spotted. 



insignia 



3. Intermediate tarsi short, not longer than their tibia?; thorax en- 

 tirely black; dorsal segments 1-3 with a small lateral spot only. 



cinerea. 



Intermediate tarsi longer than their tibia?; thorax more or less yel- 

 low ; abdomen usually with prominent maculations 4 



4. Seventh ventral segment apically produced into a spine (intermedi- 

 ate tibia? not serrate) 5 



Seventh ventral segment otherwise formed (3 



5. Markings bright yellow, those on ventral segments of abdomen 

 broad, continuous; spine of seventh ventral segment pointed at 



apex occidentalis. 



Markings greeuish-white those on ventral abdominal segments 

 broad at the sides only, connected by a narrow apical line ; spine 

 of seventh ventral segment bifurcate at apex pruinosa. 



6. Antennal joints not dentate or spinose beneath 7 



Antenna! joints more or less dentate or spinose 8 



7. Intermediate femora serrate beneath; middle-segmeut never yel- 

 low above; mesopleura? with a small yellowish spot; abdomen 



tolerably hairy texana. 



Intermediate femora unarmed ; middle-segment usually with a 

 semicircular yellow line above, and the mesopleura? generally 

 with a large spot ; abdomen very hairy troglodytes. 



8. Prominence of sixth ventral segment bifid ; stipes of genitalia 



very broad, broadly truncate at apex . . ainoena. 



Prominence of sixth ventral segment simple; stipes of genitalia 

 otherwise formed 9 



9. Dorsuluni spotted medially 10 



Dorsulurn not spotted medially 11 



10. Dorsulum with two spots anteriorly in the middle; second and 

 seventh ventral segments with a large prominence medially ; 

 stipes of genitalia as in Plate XIV, fig. 4 ; first joint of medial 



taM normal Sayi. 



Dorsulum with the yellow forming a U ; second ventral segment 

 smooth, the seventh bearing two converging ridges ; stipes of 

 genitalia as in Plate XIV, tig. 5 ; first joint of medial tarsi 

 strongly curved U-scripia. 



11. Second ventral segment with a huge prominence in the middle . 12 

 Second ventral segment at the most with a ridge in the middle. 



13 



