NATURAL SCIENCES OP PHILADELPHIA. 371 



9 23^32 mill. Seta J 1 1823 mill. ; 9 1726 mill. Length anterior leg 

 r^ 9J mill.; 9 (same size) 7^ mill. Described from six <^\ nine 9- Say 

 says, " Vertex with a small black spot each side on the orbit." Did he refer to 

 the orbits of the ocelli ? There are no other spots on the head in my species. 

 His description was posthumously published, and lacks the word " brown" or 

 " piceous''' at the end. 



The (^ 9 subimago, which are undescribed by Say, and from which I have 

 bred numerous specimens of the imago, differ from the imago as follows : The 

 $ body is often of an obscure grayish fuscous color, the lateral markings of 

 the abdomen, when present, being more obscure than in the imago ; in the 

 9 these markings are never visible. The eyes of the living tf insect are sepa- 

 rated by a narrow fissure, sometimes visible even in the dried specimen, 

 whereas, in ^ imago they are always contiguous. The abdominal setae are 

 greenish obscure, sometimes a little dusky at tip, always pilose under the 

 lens. The anterior legs $ 9 do not differ in length from one another, and are 

 generally entirely fuscous, except the base of the first and sometimes of the 

 second tarsal joints. The wings are clouded with dusky, especially towards 

 the tips; veins and cross-veins dusky, rather coarse, subequal; all the cross- 

 veins bordered with fuscous; hind wings conspicuously and widely berdered 

 with fuscous behind. 



Length J 1 8 11$ mill. ; 9 9 12J mill. Alar exp. $ 2024 mill.; 9 2G 32 

 mill. Setse J 1 12 14 mill. ; 9 10 14 mill. Eight <j\ five 9 . Differs from 

 B. ignava, Hagen (a subimago) chiefly in the feet not being rufous. 



B.etis sicca, n. sp. (^ Ferruginous. Head light ferruginous ; seta pale ; 

 eyes in the dried specimen blackish ; orbits of ocelli not conspicuously darker 

 inside. Thorax piceous ; pleura ferruginous ; sternum piceous. Abdomen 

 piceous above, except the last segment ; setae pale greenish, slenderly incised 

 with fuscous; anal appendages a little darker towards the tip. Anterior legs 

 short, piceous, except the tip of the tibia, which is black, and the first tarsal 

 joint, which is always conspicuously pale, except at the incisures ; four posterior 

 legs pale greenish, extreme tarsal tips cloudy. Wings hyaline, veins and cross- 

 veins subequal, rather fine, fuscous, in a very mature specimen pale fuscous. 



The 9 differs from tf la tne thorax and abdomen being immaculate, and in 

 the anterior tarsi being pale fuscous, except the first joint, which is pale as in tf. 



Length J* 8110 mill. ; 98^ 11 J mill. Alar exp. rf 1922 mill.; 92327 

 mill. Seta $ 19 mill. ; 9 15m ^- Anterior leg mature ^ 6 mill. ; 9( s ' m i' ar 

 size) 5 mill. Three ^, two 9 ^ a J be easily confounded at first sight with 

 arida, but is sufficiently distinct by the short anterior ^ legs, the pale first 

 tarsal joint in $ 9 anterior legs and the fuscous tf wing-veins. This, as 

 well a.s.arida, Say, differs from vicaria, Walker, and annulata, Walker, in the four 

 posterior legs not being two- or more banded, and in some other respects. 



The tf 9 subimago are scarcely distinguishable from those of arida, but the 

 eyes of the living $ are contiguous. The species occurs a month later than 

 arida. 



\\ Bcetis. Subgenus C. First tarsal joint indistinct, connate, moderate, equal 

 to about joint 2, except in anterior <^ tarsus, where it is about i ; joints 

 2 4, moderately diminishing in length in all $ 9 ^ e S 3 - ^ intermediate 

 seta visible, even in the living insect. 



B.etis debilis? Walker, Catal. tf Ferruginous. Eyes in the living insect 

 with their lower fourth fuscous and their upper three-fourths brown, and with 

 coarser facets ; seta of antennas dusky, pale at tip. Thorax geuerally piceous. 

 Abdomen with the terminal third or half of each joint more or less piceous ; anal 

 appendages pale ; seta whitish, immaculate. Leg3 pale greenish, with a median 

 narrow band on the femora, and generally the knees, fuscous; the anterior legs 

 generally with the tips of the tibia and tarsal incisures and tips fuscous ; the 

 four hind legs with only the tarsal tips fuscous. Wings hyaline; veins and 



1862.] 



