270 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



From other species with the ventral keel, 

 such as attrrima, this new species may be 

 distinguished readily by the situation of the 

 ventral keel immediately under the face of 

 the clasper and also by the heavily sclero- 

 tized, serrate, lateral process of the tenth 

 tergite. 



Male. — Length 6 mm. Color very dark 

 brown, the legs whitish yellow except for 

 the tarsi and spurs, which are brown; wings 



Fig. 911. — Chimarra elia, male genitalia. 



without perceptible pattern ; in life the in- 

 sect looks almost black. General structure 

 typical for genus. Male genitalia as in fig. 

 911. Ninth and tenth tergites fused, the 

 anterior margin of the ninth with a short, 

 stout, somewhat hook-shaped apodeme, the 

 tenth tergite forming an irregular, almost 

 membranous hood over the apex of aedea- 

 gus; ventrad of this hood are situated the 

 small, round cerci and, beyond these, the lat- 

 eral margin of the segment is produced into 

 a sharp, minutely serrate point. Ninth 

 sternite triangular, the apico-mesal line 

 bearing a long, projecting, sharp keel which 

 is slightly serrulate, is situated directly be- 

 low the base of the claspers and occupies 

 most of the exposed ventral margin of the 

 sternite. Claspers somewhat triangular, 

 the dorsal corner rounded and bearing sev- 

 eral fairly long setae, the remainder of the 

 clasper with shorter setae, the dorsal sur- 

 face of the apico-mesal corner with a 

 slender but strong black spine. Aedeagus 

 typical in general proportions for the ater- 

 rima group, having the somewhat expanded 

 internal base, beyond which it is cylindrical, 

 the exserted apex membranous and narrow, 

 not sclerotized. 



Holotype, male. — Spring-fed stream west 

 of Brackettville, Texas: April 17, 1939, 

 H. H. & J. A. Ross. 



Chimarra florida new species 



This species is a close relative of obscura, 

 differing from it, however, in the short 

 mesal process of the ninth sternite, the 

 longer claspers, which are wider at base 

 and more slender at apex, and the longer 

 and stouter lateral processes of the tenth 

 tergite. From species of the aterrinia group 

 which also have the short mesal process of 

 the ninth sternite, this new species may 

 be distinguished by the hooked aedeagus. 



Male. — Length 7 mm. Color black, the 

 wings without pattern, the femora some- 

 times brownish. General structure typical 

 for genus. Male genitalia as in fig. 912. 

 Tenth tergite with central part membranous, 

 lateral area developed into strongly sclero- 

 tized curved processes rounded at apex; at 

 the base of these is a ridgelike area repre- 

 senting the cerci. Ninth sternite produced 

 dorsad to base of tenth tergite, narrow and 

 sinuate, with a short, meso-ventral keel 

 situated near base of segment. Claspers 

 with ventral portion flared and somewhat 

 saucer-like, its lateral margin appearing defi- 

 nitely crenulate due to the presence of fairly 

 evenly spaced small humps, each bearing a 

 large seta; dorsal portion of clasper elon- 

 gate and evenly curved. Aedeagus with 

 basal portion long and irregular, developed 

 at apex into a single stout sclerotized hook. 



Female. — Size, color and general struc- 

 ture as for male. Genitalia very similar 

 to those of obscura; reliable characters to 

 separate the two have not been found. 



Holotype, male. — Five miles southeast 

 of Roberta, Georgia: May 4, 1939, P. W. 

 Fattig. 



Allotype, female. — Same data as for 

 holotype. 



Paratypes. — Florida. — Freeport, Wal- 

 ton County: April 3, 1938, L. Berner, 1 $. 



Georgia. — Same data as for holotype, 

 45, 1$. 



Fig. 912. — Chimarra florida, male genitalia. 



