THE DIPTEROUS GENUS DOLICHOPUS IN NORTH AMERICA. 29 



30. Middle basitarsi with a bristle above No. 38, bisctosus, new species. 



Middle basitarsi without a bristle above No. 25, beatus, new species. 



31. Middlebasitarsi with a large bristle above (western).. No. 20, corax Osten Sacken. 

 Middle basitarsi without a bristle above 32. 



32. Middle tibiae with one bristle below; bend in last section of fourth vein not un- 



usually small No. 24, acuminatus Loew. 



Middle tibiae with more than one bristle oelow; bend in last section of fourth 

 vein very small 33. 



33. Hoad with two yellow bristles on each side near the proboscis, 



No. 41, aequalis, new species. 

 Head without yellow bristles below No. 59, nodipennis, new species. 



34. Hind tibiae mostly or wholly black 35. 



Hind tibiae largely yellow 43. 



35. Middle and hind femora each with two or three preapical bristles 36. 



Middle and hind femora each with one preapical bristle 37. 



36. Middle and hind femora each with three preapical bristles. 



No. 47, partitus Melander and Barnes. 

 Middle and hind femora each with two preapical bristles. 



No. 54, remus, new species. 



37. Front violet, or at least bluish 38. 



Front green 40. 



38. Fore and middle tarsi black from the tip of the first joint, sometimes brown almost 



to the base No. 55, adultus, new species. 



Fore and middle tarsi almost wholly yellow 39. 



39. Hind tibiae with the yellow on upper edge reaching their middle, or nearly so. 



No. 29, grains Loew. 



Yellow on upper edge of hind tibiae reaching one-fourth or less than one-fourth 



their length No. 30, calcaratus Aldrich. 



40. Hind tibiae almost wholly black, only a very little yellowish at extreme base; 



wings distinctly and rather uniformly brownish No. 32, jo/msom Aldrich. 



Yellow of hind tibiae extending along the upper edge for some distance at least; 

 wings grayish, not tinged with brown 41. 



41. Middle tarsi infuscated almost from their base; fore tarsi black from the tip of the 



first joint No. 58, laticornis Loew. 



Fore and middle tarsi almost wholly yellow 42. 



42. Hind tibiae with the yellow on their upper edge extending to their middle, or 



nearly so No. 29, gratus Loew. 



Yellow of hind tibiae reaching only to basal fourth or slightly more. 



No. 30, calcaratus Aldrich. 



43. Fore tarsi black from the tip of the first joint, or wholly black 44. 



Fore tarsi only a little darkened at tip 46. 



44. Hind femora with two preapical bristles; bristles on lower part of the head all 



black No. 36, nubifer, new species. 



Hind femora each with one preapical bristle; head with two yellow or whitish 

 bristles near the proboscis 45. 



45. Last section of fourth vein nearly straight, only a little bent. 



No. 41, aequalis, new species. 

 Bend in last section of fourth vein small but quite abrupt. 



No. 46, alacer, new species. 



46. Fore tibiae with two or three bristles on the lower anterior edge ; bristles on lower 



part of the head all black No. 49, retinens, new species. 



Fore tibiae with only one small bristle below; head with two yellowish bristles 

 below each side of the proboscis No. 46, alacer, new species. 



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