18 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.60. 



Some specimens vary in color from the general green color to a 

 decided bronze with a reddish reflection in certain lights. 



Ty'pe locality. — Jacumba Spring, California, June 28, 1917, J. M. 

 Aldrich, collector. 



Distribution. — Garfield, Utah, July 9, 1911 ; Lake Elsinore, Cali- 

 fornia, August 2, 1911 ; Tempe, Arizona, June 19 to 21, 1917; Saltair, 

 Utah; Great Salt Lake, July 5, 1919, J. M. Aldrich, collector. Los 

 Cerritos, California, April 7, 1915 ; San Diego County, Desert Edge, 

 California, April 1915, M. C. Van Duzee, collector. Two specimens 

 labeled "Laguna, Calif." and one specimen labeled "Aliso, C." No 

 date nor collector's name given. 



Type., male. — Allotype, female and fourteen para types. Cat. No, 

 24134, U.S.N.M. 



Allied to T. vorax Loew but easily separated from that species by 

 being a brighter green, without the spot in the wing and by having 

 the middle tarsi greatly modified. 



13. TACKYTRECHUS ANGUSTIPENNIS Lo«w. 



TacJiytrecJius anpustipetmis Lop:w, Centuries, 1S61, pt. 2, p. 83, No. 64. 

 TacUytreclius angustipennis Loew, Aldrich, Trans. Amer. Ent. Soc, 1898, 

 vol. 23, p. 82. 



Male. — Face broad, reaching slightly below lower edge of eyes; 

 pale, dull, yellow dust, just below the antennae ; about two-thirds as 

 wide as at lower end. Front dusted with green and brown according 

 to the light. Ocelli deep yellow. Antennae small, black, second 

 joint the smallest. Arista black. Orbital cilia black on apical 

 fourth, white on lower three-fourths. Thorax, dorsum, green, cov- 

 ered with a grayish ocher-yellow dust, which makes the green ground 

 color but little apparent ; in the middle are two brown longitudinal 

 lines, which diverge a little behind and are very much shortened ; 

 the single bristles are inserted upon brownish-black spots. In cer- 

 tain lights there are several small yellowish-white spots. Scutellum 

 a little more brown than the dorsum of the thorax. Abdomen green, 

 covered with a rather thick whitish dust, giving it a checkered ap- 

 pearance ; in certain lights the middle line and posterior edges of the 

 segments appear almost black. Hypopygium black, with whitish 

 dust ; lamellae of moderate size, rounded oval, with short black hairs. 

 Coxae black with yellowish-white dust, fore coxae beset with ex- 

 tremely short, delicate, sparse hairs; on inner side at apex are a 

 few stiff, long, black bristles. Femora and tibiae greenish or bluish, 

 with a little silver dust, tarsi more of a blackish. Knees reddish. 

 On the hind side of the hind tibiae are two or three remarkably 

 flattened bristles. Wings long and narrow, the costa distinctly 

 thickened upon the middle of the first section. Halteres deep yel- 

 low, darker at the base. Tegidae pale yellow, cilia long and black. 



Length 4 mm. 



