AET. 12 KFAS TO SAPfiOMYZlDAE MALLOCH a:ND McATEE. 5 



17. Frontal lunule bare ; fringes of calyptrae brown ; interfrontalia with two 

 series of incurved hairs on center; glossy portion of upper orbits micro- 

 scopically strigose aberrans Malloch. 



Frontal lunule with setulose hairs at least on the sides except in nigro- 

 ciliata; fringes of calyptrae whitish or yellowish except in nigrociliata 

 and subpolita; glossy portion of upper orbits usually smooth (compare 



occidentalis and coloradensis) 18 



IS. No minute hairs between the apical pair of scutellar bristles; third antennal 



segment not or barely over twice as long as its greatest width 19 



Some minute hairs between the apical pair of scutellar bristles ; third 



antennal segment more than twice as long as its greatest width 20 



19. Tarsi brown ; larger species, fully 4 mm. in length marylandica Malloch. 



Tarsi pale yellow; smaller species, less than 4 mm. in length. 



laticornis Meigen. 



1*0. Fringes of calyptrae fuscous 21 



Fringes of calyptrae white or yellow; thorax and abdomen bluish 22 



21. Frontal lunule bare; head and thorax black, ab-domen slightly bluish, 



nigrociliata Malloch. 

 Frontal lunule hairy ; thorax and abdomen blackish blue subpolita Malloch. 



22. Width of male frons at anterior margin equal to at least half the entire 



length of frons ; preapical dorsal pair of hairs on ovipositor very long ; 

 hairs at angle of calyptrae much longer than rest of fringe; upper 



orbits largely microscopically strigose occidentalis Malloch. 



Width of male frons at anterior margin not nearly equal to half its entire 

 length ; preapical dorsal hairs on ovipositor very short ; fringes of 

 calyptrae of uniform length 23 



23. Third antennal segment about twice as long as wide; upper frontal orbits 



granulose coloradensis Malloch. 



Third antennal segment at least three times as long as wide ; upper frontal 

 orbits largely or entirely polished 24 



24. Only the basal segment of each tarsus yellow longlcornis Williston. 



Basal two or three segments of each tarsus yellow 25 



25. Larger species, over 4 mm. in length ; hypopygium as in Figure 3, 



nndif emorata Malloch. 



Smaller species, less than 4 mm. in length; hypopygium of male as in 



Figure 1 polita Say. 



LIST OF SPECIES OF THE DISTRICT OF COLUMBIA REGION. 



L. aberrans Malloch. — Mount Vernon, Virginia, April 19, 1917, 

 McAtee, 



* L. albiceps Malloch. — Washington, District of Columbia, May 

 29, 1912, McAtee. 



L. laticornis Meigen. — Common and widely distributed; dates of 

 collection range from May 8 to October 3 ; comes to light. P. I. 



* L. marylandica Malloch. — Plummer Island, Maryland, bred 

 April 24, 1915, from larva collected under bark, April 7, H. S. 

 Barber. 



* L. nudif emorata Malloch. — Plummer Island, Maryland, April 

 21, 1912, McAtee ; Falls Church, Virginia, May 10, N. Banks. 



Z. polita Say. — The most numerous species; the season for active^ 

 imagines runs from March 29 to October 29 ; the species ha& beert 



