296 MAINE AGRICULTURAL EXPERIMENT STATION. 1917. 



aphid to which to refer it. It is not the avenae of American 

 authors which has well denned characteristic dark green longi- 

 tudinal streaks entirely absent in pseudoavenae. It is not the 

 avenae of Theobald (Canadian Entomologist, 1916 p. 235). It 

 is not the padi described and figured by Koch and Buckton. Is 

 it the padi of Van der Goot (1915 p. 241) ? Possibly, "in part", 

 though it is certainly not in accord with his collection from 

 Mespilus and Pirus mains. 



No such aphid has previously been recorded on its spring 

 host in this country as it is none of the species listed from choke 

 cherry. 



That it has been taken on grain and confused with the 

 apple grain aphid, the so called "avenae" of American authors 

 seems not improbable as these two species are so much alike in 

 structural characters that they would be distinguished with diffi- 

 culty from mounted material. In life, however, they are readily 

 separable especially in the spring generations with a simple hand 

 lens, the characteristic dark green longitudinal lines of our so 

 called "avenae" being entirely absent from all generations of 

 pseudoavenae and the powder areas of the spring generations 

 of pseudoavenae being particularly noticeable. Both species 

 have a rusty internal area near the bases of the cornicles. 



To designate this aphid as a new species seems the only 

 way. to preserve its life cycle from confusion at present. 



