260 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



-. Last section of the fifth vein one and a half times as long as the 



cross-vein 27 



27. Tegular cilia pale maurus Wh. 



-. Tegular cilia black cterulescens Malloch. 



28. Abdomen blue ~^ 



-. Abdomen bronzed, green or black 30 



29. Thorax with yellowish vittae; antennae black aurivittatus^ Wh. 



-. Thorax with opaque gray pollen; antennae with first two joints 



yellow cyanogaster Wh. 



30. Males and females 31 



-. Males only zl 



31. Thorax with distinct vittae 32 



-. Thorax without distinct vittae ^' 



32. Last segment of the fifth vein only half as long as the cross-vein. . 



.; princeps Wh. 



-. Last segment of the fifth vein as long or longer than the cross- 

 vein 33 



33. Last segment of the fifth vein about the same length as the cross- 



vein 34 



-. Last segment a little longer than the cross-vein 36 



34. Legs and feet wholly black ; knobs of halteres infuscated 



tnodestus V. D. 



-. Tips of femora, tibiae, base of tarsi and knobs of halteres yellow . . 35 



35. Tips of third and fourth veins close together (typical of genus) . . 



calif orniensis Wh. 



-. Tips of third and fourth veins a little wider apart than is usual 

 in the genus "veles Loew. 



36. Abdomen and pleurae black ; face opaque ; thoracic vittae very dis- 



tinct; tips of third and fourth veins rather widely separated 



veles Loew. 



-. Abdomen, pleurae and face distinctly green ; thoracic vittae less dis- 

 tinct; tips of third and fourth veins close together (as is usual 

 in the genus) distinctus V. D. 



37. Legs yellow ; cross-vein angulated at its center and with a stump- 



vein appendiculatus Wh. 



-. Legs black ; cross-vein normal 38 



38. Knobs of halteres infuscated, at kast on one side, .tnodestus V. D. 



-. Knobs of halteres yellow 39 



39. Last section of fifth vein only half as long as the cross-vein 



xerophilus Wh. 



-. Last section of fifth vein a little longer than the cross-vein (speci- 

 mens in which the thoracic vittae are almost obsolete) 



veles Loew. 



40. Posterior cross- vein with a stump- vein near its middle 



xerophilus Wh. 



-. Cross-vein normal ^1 



41. Hind matatarsus with a small tooth near its base 42 



-. Hind metatarsus without such a projection, not narrowed at base. . 43 



42. Small species, 2 mm.; third and fourth veins rather widely sep- 



arated ; "v^^^s Loew. 



-. Larger species, over 3 mm. ; third and fourth veins normal. 



calif orniensis Wh. 



43. Last section of fifth vein one half the length of the cross-vein 



xerophilus Wh. 



-. Last section of fifth vein and the cross-vein of nearly equal length. 

 tnodestus V. D. 



