No. 64] DirTERA OF CONNECTICUT : TAXONOMY 391 



heavy dark brown pattern that is chiefly costal; branches of M verv 

 strongly divergent, so cell 1st Mo is about as wide as long. S. L. 

 about 22 mm.; w. 18 mm. 9. L. about 80 mm.: w. 20 nun. 



(May, juiv.') Mass., Ct., southw. to n. Fla. 



Connecticut.— Farmington, June 7, 1914 (W. M.) ; Type: Storrs, without more- 

 exact data. 



Subgenus Prionolabis Osten Sacken 



1859. Limnophila (Ptionolabis) Osten Sacken; Proc. Acad. Nat. Sci. 

 Philadelphia, 1859 : 239. 



The subgenus Prionolabis is represented in the local fauna by six 

 species, with several others occurring in Eastern Asia. The most aber- 

 rant species is mundoides whose male hyi^opygium is very remarkable 

 and deviates so greatly from that of the subgenotype that it w'ill very 

 probablj' require a new group name. L. irvwula and L. terebrans also 

 depart in some respects from the accepted characters of the group, but 

 undoubtedly belong here. The typical group of Prionolabis includes 

 the type of the subgenus, tnifibasis, together with simplex and loalleyi. 

 In these three species, the characters of a comb-like outer dististyle 

 and a highly compressed aedeagus are found in the male genitalia. 

 This flattened nature of the aedeagus is closely approached by certain 

 species of the subgenus Phylidorea {platyphalhis grou})). indicating a 

 probable relationship. All local species of Prionolahii< have the an- 

 tennae short in both sexes. The adult flies are found resting on veg- 

 etation in open woods, usually near water. The early stages are still 



unknown. 



Key to Species 

 (Based chiefly on male characters) 



1. Mesonotum polished black 2 



Mesonotuni with a gray pruinosity 3 



2. Wings with a brownish tinge, patterned with darker brown along cord, outer 



end of cell 1st ilf- and vein C«i; legs stout, conspicuously hairy: femora 

 dull brownish yellow, narrowly tipped with dark brown : male hypopygium 



of normal limnophiline appearance munda 



Wings hyaline or nearly so, unmarked except for the stigmal darkening: 

 legs slender, without conspicuous setae ; femora dark brown, with onl\ tlie 

 extreme bases paler : male hvpopvgium enlarged and very complicated in 

 structure mundoides 



3. Male hypopygium with the outer dististyle not pectinate : legs of female 



short clothed with long conspicuous setae; size small (wing, $, under 8 



mm.) terebrans 



Male hypopygium with the outer dististyle bearmg a series of comb-hke 

 teeth along inner margin of distal half; legs of both sexes long and slender, 

 with normal vestiture : size generally larger (wing. 6. m all except n'aUeyi. 

 over 9 mm. ) .•■•.••••. ■ ■ • ' 



4 Male hyoopygium with the inner dististyle simple, termniatnig in a single 



• <.'r\7:„ AC, \f\ simplex 



point ( r ig. 4o, M ) -r' ' V-' ' ' \'c' \' ' Vt \ =; 



Male hypopygium with the inner dististyle bifid (Fig. 45, L, N) 3 



5 Size large (wing over 9 and usually over 10 mm.) : male hypopygium witli 



the inner dististyle bearing conspicuous erect serrations, 'the inner arm 



slender (Fig 45, L) ; wings with a dark seam along vein Oh rufibasis 



Size smaller (wing under 8.5 mm.) : male hypopygium with the inner dististyle 

 having both arms short and obtuse, the outer with short appresscd serra- 

 tions (Fig 45 N) ; wings without a darkened seam along vein Ch, walleyi 



