4 PEOCEEDINGS OP THE NATIONAL MUSEUM tol. 73 



KBT TO SPBCIES OF BBLTOSIA 



1. Fourth abdominal segment wholly shining black, the usual pollen absent 2. 



Fourth abdominal segment black, with a conspicuous large spot of pale pollen 



above, which does not extend down the sides nor reach the tip ; abdomen 



elsewhere black (Argentina, Brazil) weyenberghiana Van der Wulp. 



Fourth abdominal segment densely poUinose on basal half or more, the 

 pollen extending down the sides and ranging in color from almost white 

 to reddish orange 3. 



2. Second abdominal segment with two or three pairs of spinelike median mar- 



ginal bristles; large, spinose, robust species (Bolivia) __manni, new species. 

 Second abdominal segment with a continuous marginal row of about 18 

 bristles; medium-sized, less spinose species (south Brazil). 



australis, new species. 



3. Both third and fourth abdominal segments with pollen of deep orange or 



reddish color 4. 



Pollen not alike on the two segments, or else paler, at most golden 5. 



4. Pollen of head brown except facial ridges and a spot on parafacial, where it 



is silvery (San Domingo) vanderwulpi Williston. 



Pollen of head silvery white (Jamaica) ferruginosa Townsend. 



5. The small hairs below lowest frontals are pale and delicate 6. 



These hairs are black and generally less delicate 14. 



6. Fourth abdominal segment wholly pale poUinose to apex 7. 



Fourth abdominal segment with the tip black, including bases of marginal 



bristles (south Florida) slossonae Ooquillett. 



7. Third and fourth segments of abdomen with broad, uninterrupted cross- 



bands of dense yellow pollen ; basal abdominal segments black 8. 



Third segment not strongly contrasting with second, the band if broad 

 clearly interrupted; abdomen generaly more reddish or yellow in ground 

 color • 9. 



8. Third segment densely yellow poUinose to tip, like the fourth (United 



States) semiflava, new species. 



Third segment black at tip (Mexico, Brazil) mexicana, new species. 



9. Second abdominal segment shining translucent yeUow, with median black 



stripe (Porto Rico, Peru) luteola Ooquillett. 



Second abdominal segment with obvious pollen over most of its surface, or 

 black in ground color 10. 



10. Ground color of abdomen yellow (Mexico, Panama). 



ochriventris Van der Wulp. 



Ground color of abdomen black, sometimes tending toward reddish but not 



yellow 11. 



11. Male without orbitals {recticomia Macquart) 12. 



Male with orbitals 13. 



12. Third antennal joint black (Mexico, Peru, Ecuador) — recticornis Macquart. 

 Third antennal joint almost entirely red (Brazil). 



recticornis var. ruficornis, new. 



13. Third antennal joint six times the second in the male, in the female three 



times; male pulvilli small (Paraguay, Brazil) fosteri Townsend. 



Third antennal joint hardly three times the second in the male, twice in the 

 female; front pulvilli in male longer than last tarsal joint (Peru, Guate- 

 mala, Porto Rico) equinoctialis Townsend. 



14. Fourth abdominal segment with dense yellow pollen to tip 15. 



Fourth abdominal segment black at tip, including the bases of the marginal 



bristles 22. 



