AMERICAN DIFTERA. 285 



Several specimens, Brookings, S. D., and New Bedford, Mass., 

 the latter from Dr. Hough. 



This species is almost identical with inermis Loew, except that 

 the male has yellow femora, like the female. 



Guerin-Menevelle, Voyage sur la Cowette, 1838, 293. 

 Aldrich, Kans. Univ. Quart., II, 48, 1893 (Gnamptopsilopus) ; Can. Eut., Aug., 



1904, 246. 



TABLE OF NORTH AMERICAN SPECIES. 



1. Antennje entirely black 2. 



At least the basal joints yellow 6. 



2. Femora yelloy? 3. 



Femora black 5. 



3. Fore coxae with black bristles at tip (Mex.) Infiiniatiini Aldrich. 



Fore coxse with pale bristles at the tip 4. 



4. Base of hind coxfe atid hind margin of pleura pale (U. S. )■ -costalis n. sp. 

 Base of hind coxfe and hind margin of pleura dark (U. S.). 



scintillans Loew. 



5. Wings without black markings (Mex.)... ciliipennis Aldrich. 



Wings black, except apex and hind margin (Mex.) ■ .climidiatiiiii Loew. 



6. Dorsum of thorax yellow, with a green or blue stripe 7. 



Dorsum of thorax wholly metallic 8. 



7. Pleura yellow; middle tibia- and metatarsi with erect cilia (W. I.). 



flaTidum Aldrich. 

 Pleura with an indistinct dark spot; tarsi plain (W. I.), .florsale Loew. 



8. Thoracic dorsum opaque, dusted ; abdomen not pale at base (U. S.). 



pal lens Loew. 

 Thoracic dorsum shining, abdomen usually pale at base 9. 



9. Middle coxjb infuscated on outer side at least to middle 10. 



Middle coxae wholly or almost wholly yellow 13. 



10. Costa of male ciliated, with an angular projection forward near the tip (U.S.). 



p.<«if,taciniim Loew. 

 Costa of mal^ without such projection 11. 



11. Middle femora of male shortened, dark at base, the tibiae elongate (U. S.). 



filipes Loew. 

 Middle femora of male normal, pale 12. 



12. Abdomen pale at base above (U. S., Cuba) variegalum Loew. 



Abdomen not pale at base above (Cuba) castiiin Loew. 



13. Fore femora with slender erect bristles below (U. S. ) teiier Loew. 



Fore femora not with such bristles 14 



14. Hind margin of pleura yellow 15 



Hind margin of pleura green (Mex.) mexicaiiuin Aldrich. 



1.5. Abdomen above with basal yellow baud, remainder green (U. S.). 



(bicolor Loew) unifasoiatuili Say. 

 Abdomen with several bands, including the greater part of first four seg- 

 ments (U. S.) rolundiceps n. sp. 



TRANS. AM. ENT. 80C. XXX. NOVEMBEK. 1904. 



