No. 64] DIPTERA OF CONNECTICUT : TAXONOMY 417 



Key to Species 



1. Cell J/i of wings present (Fig. 44, L, N) 2 



Cell Ml of wings lacking ( Fig. 44, M ) 5 



2. Tarsi snowy-white 3 



Tarsi not white 4 



3. Wings strongly tinged with brown; antennae ( $ ) more than half the length 



of body; first flagellar segment more than three times the length of head. 



albitarsis 

 Wings subhyaline or but weakly suffused with darker; antennae of both 

 sexes less than one-half the length of body; first flagellar segment about 

 twice the length of head brevioricornis 



4. Antennae ( $) elongate, approximately three times the body; wings grayish 



brown ; vertical tubercle very prominent spinosa 



Antennae short in both sexes, extending about to the w^ing-root or a little 

 beyond ; wings darker brown ; vertical tubercle low brachycera 



5. General coloration of body yellow or yellowish red o 



General coloration of body gray, brown or black 7 



6. Wings with a weak yellowish tinge, the stigma pale brown ; antennae ( c5 ) 



elongate, about one-half longer than the body ; dorso-pleural membrane 



and a spot on lateral margin of scutum velvety-black wilsonii 



Wings with a strong brownish yellow suffusion, the stigma conspicuous, 

 dark brown ; antennae short in both sexes ; in cases a small to nearly 

 obsolete brownish spot on lateral margin of scutum a u rata 



7. Wings with distal section of vein Cui unusually long, nearly twice ui-cn. 



alberta 

 Wings with the distal section of C»i sliort, subequal to or shorter than 

 m-cu 8 



8. i?a far before fork of Ri^i, the latter subequal to or longer than A'^.^, cell 



Ri correspondingly shortened fultonensis 



7?2 close to or beyond fork of 7^2+3+4, vein R^^i being obliterated or very 

 short, cell Rs correspondingly lengthened y 



9. R2 some distance beyond the fork of i?2+3+4, R-m much longer than R^^-.; 



vein Ri usually with abundant macrotrichia throughout its length : anten- 

 nae {$) elongated; ovipositor with elongate chitinized valves ....cinerea 

 Ro close to fork of i^s+s+i, i?2+3 very short or lacking ; no macrotrichia on Rs 

 or either of its anterior branches (excepting two or tiiree in some speci- 

 mens of gihbosa) ; antennae ( $ ) short, elongate only in $ of longiconiis 

 which has ovipositor with short fleshy valves 10 



10. General coloration of thoracic dorsum dark brown or black, without pruinos- 



ity; vertical tubercle polished black; wings with a strong blackish 



suffusion .tristis 



General coloration of thoracic dorsum gray or brownish gray; vertical 

 tubercle opaque, concolorous with remainder of vertex: wings not uni- 

 formly suffused with blackish 1 1 



11. Knobs of halteres whitish; wnngs, especially of males, widest opposite the 



level of vein 2nd A : antennae ( $ ) very elongate (longicornis) or short 



(gaspcnsts) ; ovipositor w^ith short fleshy valves • ■ - • 12 



Knobs of halteres dark brown; wings widest along the central half of wings 

 or opposite the distal half; antennae short in both sexes; ovipositor 

 with long chitinized valves ^-^ 



12. Antennae ( S ) very long ; wings with Sc long, Sci ending some distance 



bevond the fork of Rs: size large (wing, $, over 10 mm.) longicornis 



Antennae short in both sexes ; wings with Sc short, Sci ending about oppo- 

 site the fork of Rs; size small (wing, S. under 8 mm.) .gaspensic 



13 General coloration of mesonotum and pleura grayish brown, distinctly 



gibbosa 



prumose •' u' ' ' 1 



General coloration of mesonotum and pleura dull dark brown, with only a 

 slight vellowish gray pruinosity fuligmosa 



