August, '16] 



DOAXE: A NEW WHEAT ISOSOMA 



399 



and have used the common name of "the wheat sheath worm." A 

 brief d(\'^cription follows: 



Isosoma vaginicolum n. sp. 



Head, wholly opaque black, finely punctate, with fine white pile; antenna^ black, 

 basal segments faintly yellowish, especially below, the club somewhat shorter than 

 the three preceding segments taken together, thorax black, finely punctate, in 

 certain lights a faint 3'ellowish spot may be seen on the anterior lateral corner of the 

 prothorax; coxae and trochanters black; femorae of the first pair of legs black at 

 base, j'ellowish toward the tip, in some instances nearly all of the distal half, es- 

 pecially below, is yellowish; femorae of other legs black, yellowish at tip; anterior 

 tibiae yellowish, sometimes somewhat darker, especially below; other tibiae blackish, 

 yellowish at base and tip; tarsi yellow, last segment darker at tip; wings reaching 

 to the tip of the abdomen; abdomen shining black, extreme tip (ovipositor sheath) 

 yellowish; length 3 mm.; wing expanse 51 mm. to 6 mm. 



Isosoma grande, which is found in the same fields as /. vaginicolum, 

 may easily be distinguished from the latter species by its large size 

 and shining thorax, A few specimens of /. tritici were also found in 

 this region. They may be distinguished from /. vaginicolum by the 

 basal segment of the antennae being wholly black and the club being 



Fig. 23. Isosoma vaginicolum. 



