274 Annals Entomological Society of America [Vol. VI, 



43. Male with anterior angle of cheek produced, the vibrissse formed of a number 



of bristles, fasciculate, turned upward and generally ending in an acute 

 joint; female with the mouth margin produced anteriorly, but without a 

 fasciculus 44 



Mouth margin not produced anteriorly in either sex; male vibrissse normal. .47 



44. Large species, over 3 mm. in length; cheeks of almost equal height at anterior 



and posterior margins; antennas brownish; arista shortly and distinctly 

 swollen at base; palpi almost entirely bare. . . .42 vibrissata, new species. 

 Smaller species, generally less than 2.5 mm. in length; antennse black; arista 

 with elongate swelling; cheeks always higher anteriorly than posteri- 

 orly 45 



45. Small species, 1.5-2 mm.; frons weakly bristled; discal setulae not carried 



beyond the transverse line of the posterior pair of dorso-centrals, gen- 

 erally ceasing distinctly in front of that point 46 



Larger species, 2-2.5 mm.; frons strongly bristled; discal setulae carried at 

 least to transverse line of posterior pair of dorso-centrals generally 

 beyond that point 43 affinis, new species. 



46. Very small species, barely 1.5 mm.; vibrissas in male not very prominent; 



the anterior angle of cheeks in neither sex much produced 



44 insularis, new species. 



Larger species, about 2 mm.; vibrissas in male prominent; anterior angle of 



cheek in both sexes very distinctly produced ... 45 texana, new species. 



47. Species with four distinct pairs of dorso-central bristles on mesonotum; 



outer cross vein at barely beyond end of first vein; last section of fifth 

 vein twice as long as penultimate section. AQ'abtiormalis, new species. 

 Species with generally only two distinct, rarely three, pairs of dorso-centrals; 

 the outer cross vein at distinctly beyond end of first vein, and the last 

 section of fifth never twice as long as penultimate section 48 



48. Eyes bare 49 



Eyes with very distinct pubescence on the upper surface close to frontal 



orbits 47 virens Loew. 



49. Fore tibia with a distinct bristle on the posterior surface at about apical 



third 50 



Fore tibia without any distinct bristle at that point 51 



50. Thorax blue, abdomen bronzy-black; orbits with sparse pubescence and the 



bristles situated at nearer to the eye margin than to the inner margin; 



squamse white, fringe concolorous 48 caridea, new species. 



Thorax black; abdomen bronzy; orbits thickly pubescent, the bristles sit- 

 uated on nearer to the inner margin than to the eye margin; squamae 

 grayish, margin and fringe brown 49 hurgessi, new species. 



51. Arista with very long pubescence, much longer than basal diameter of 



arista 50 pliimiseta, new species. 



Arista with shorter pubescence, or entirely bare 52 



52. Mesonotum with three distinct pairs of dorso-centrals; large species, 3.5-4 



mm. Larva living in galls on wistaria twigs 51 websteri, new species. 



Mesonotum with only two distinct pairs of dorso-centrals; smaller species, 

 not near 4 mm., generally 2.5 to 3 mm 53 



53. Squamae grayish or brownish, margin and fringe always brown or blackish.. 54 

 Squamae whitish or yellowish, fringe concolorous 47 virens Loew. 



54. Arista distinctly pubescent, and almost as long as from its base to vertex. . 



52 longiseta, new species. 

 Arista much shorter, less distinctly pubescent 55 



55. Large species, 2-3 mm.; outer cross vein at less than its own length from 



inner, inner at distinctly beyond middle of discal cell 56 



Smaller species, distinctly less than 2 mm 57 



56. Mid tibial bristles distinct; larva in galls on lime trees... 53 tilise. Couden. 

 Mid tibial bristles absent; larva in galls on poplar trees. .54 schineri, Giraud. 



57. Mouth margin with numerous, rather strong bristles, which form a group, 



though not a fasciculus, at anterior angle... 55 congregata, new species. 

 Mouth margin with the bristles as usual, the single vibrissa diflferentiated. 



56 minima, new species. 



