INSECUTOR INSCITI^ MENSTRUUS 153 



light, fifth dark. The hind legs have the light line more 

 markedly developed than on the other legs, the basal band on 

 the second, third and fourth joints much more marked, 

 and there are sometimes a few light scales at the base of the 

 fifth. Ungues simple on all the legs. 



Wings : clear, yellowish, slightly inf uscated at the base of 

 the second long vein, and at the cross veins. The scales are 

 mostly brown, a slight admixture of white on the costa and 

 first long vein where the scales are truncate, while on the 

 remainder of the veins the scales are long lanceolate, rather 

 narrow and a dark brown, the lateral scales being especially 

 long and narrow. There are aggregations of scales forming 

 five distinct spots, one at the base of the forks of second, 

 fourth, and fifth long veins, one at the root of the second long 

 vein, and one at the cross veins. The spot at the fork of the 

 fifth vein is very distinct though small, on well scaled wings, 

 but becomes more or less indefinite with the denuding of the 

 wing. The first submarginal cell is longer and narrower than 

 the second posterior, its petiole about half the length of the 

 cell, and practically equal to that of the second posterior ; 

 cross veins nearly of one length, almost in a line, and heavily 

 scaled on the distal side. The halteres have light stems and 

 dark brown knobs. On the ventral side of the wing near the 

 root of the first long vein is a heavy bunch of long hairs or 

 slender bristles. 



Length about 10.5 mm. (body 7 mm., proboscis 3.5 mm.), 

 wing about 6 mm. 



Taken, July 8-25, 1919, at Mostovoi, Selenga, and Verkhne 

 Udinsk, Siberia. 



Described from twenty-four females sent by the Surgeons 

 at these posts. Apparently it lies nearest to C. alaskaensis to 

 which species I referred it originally, but additional specimens, 

 and further study leads me to believe it to be distinct, the most 

 marked difference being the fifth wing spot at the fork of the 

 fifth long vein ; otherwise the differences are small, but it was 

 interesting to find so nearly related a species on the Asiatic 

 side of the Pacific. 



