20 



Wheat {Triticum wdgare), rye {Secale cereale), wild rye {Elymus 

 virginieus), oat (Avena sativa), meadow grass (Poa pratense), green 

 foxtail (Setaria mridii), red top (Agrostis vulgar/*)* cheat {JBrornus 

 secalin us), orchard grass (Dactyl'* glomerata), and red clover (Trifolium 

 pratense). 



Its range thus far has been found to cover most of the northern 

 States, including Canada, east of the Mississippi, but having gradually 

 spread beyond that border as far west as Montana and South Dakota, 

 and may soon be expected to make its appearance along the Pacific 

 slope. 



Fig. 3. — Macrosiphum cerealis Kalt. : migratory female; greatly enlarged (original). 



DESCRIPTION OF THE .SPECIES. 



Apterous female. — Length of body 2 to 2.6 mm ; broadest about the middle of the 

 abdomen , tapering gradually toward the head and more rapidly posteriorly. Antennae 

 as long or slightly longer than the body; third joint shorter than the sixth and gen- 

 erally provided near the base with one or two small, circular, ami projecting sensoria; 

 all of the hairs small and simple or but slightly clavate. The legs are long and their 

 hairs short, stiff, and simple. The nectaries, as usual, are tapering and reach about 

 to the end of the abdomen. Tail long, curved upward, and almost of the length of 

 the nectaries; it is somewhat constricted about its basal third; its terminal section 

 elongate lanceolate; the surface is densely covered with minute, acute spines and 



