THE CANADIAN ENTOMOLOGIST. 



39 



variability of this species (or. as it may prove to be, the likeness of 

 several species), and the necessity of a careful study of it and allied 

 species. The writer will be greatly indebted to any who may be able to 

 aid him with material, preferably alive, for the prosecution of such a 



study. 



Thomas's S. pisi (1. c.) does not seem to be the same as N. 

 destructor, but is quite similar to the varieties described above. 



N. erigeronensis, Thos., and JV. corydalis, Oest., are very closely 

 allied to N. pisi, but specimens of them have not come under our 

 observation.* The types of neither seem to have been preserved. 



(To be continued.) 



*Addenda. — Since writing the above, Mr. O. W. Oestlund has kindly sent me 

 specimens of these species. Concerning them he remarks : 



" i. N. erigeronensis is well separated from pisi and corydalis by having- the 

 sensoria more numerous and scattered in several rows along the whole length of 

 joint III., and bv being raised above the surface or forming distinct protuberances. 

 Front femur much shorter (0.70 mm.). Front wings shorter. Spur (VII.) of 

 antenna equal to or not much longer than III. 



" 2. N. pisi is a much larger form. Sensoria less numerous ( 15 18) and nearly 

 in a single row, and almost absent on apical ^3 of segment ; not forming 

 protuberances. Front femur much longer. Front wings larger. Spur much 

 longer than III. (1.20 \\ 0.90). 



" 3. N. corydalis comes very close to pisi, and possibly too close to stand, 

 though in the general aspect of the insect it seems quite distinct. Size smaller. 

 Sensoria fewer in number (12-15) anc l m a single row. Front femur, front wings, 

 and spur much as in pisi.'' 



The specimens sent me measured as follows : 



Description. 



N. pisi 



N. corydalis .... 

 N. erigeronensis 



85 



95 

 64 

 66 

 76 



All were collected at Minneapolis, Minn. 



This A T .pisi is similar to Nos. 12, 13, etc. above, taken on lettuce, and shows 

 the same differences between it and var. destructor. The specimens were collected 

 on squash. The apterous viviparous female has 5 to 8 sensoria on III. 



N. corydalis seems similar to No. 15 above. It does not differ materially 

 from Oestlund's pisi (as he remarks), and I think it merely a variation, possibly a 

 distinct variety. 



N. erigeronensis is a quite distinct species. In the apterous viviparous female 

 the cornicles are thicker, more finely reticulated at apex than \npisi, are blackish, 

 reach beyond the cauda, curving outward ; antenna? dark, 9 to 15 sensoria on 

 proximal half of III. In the winged viviparous female the antennae, tibia?, distal 

 half of femora, apical ~A> °f cornicles are blackish, cornicles reach to tip of cauda ; 

 sensoria numerous (20 or so) on III., and protuberant ; capitate hairs scattering 

 on antenna; and bodv. E. D. S. 



