A SYNOPSIS OF THE APHIDIDAE 35 



any further comment. He once thought the western spe*cies was iden- 

 tical with Thomasia salicicola (Essig), to which Morrison considers 

 it very closely related, but Davidson assures him the two are distinct. 



13. Genus Micrella Essig 



Essig, Pom. Jour. Ent., vol. 4, p. 716, 1912. Type M. monella n.sp. 



30. Micrella monella Essig 



Figures 70, 72 



Essig, Pom. Jour. Ent., vol. 4, p. 717, 1912 (orig. desc.). 

 Becords. Salix lasiolepis, Oxnard (Essig); S. laevigata, Santa Paula (Essig). 



This species was taken twice by Essig, who described it, in 1910 

 near Oxnard, and in 1911 near Santa Paula. Since then it has never 

 again been found. The author has had access to cotype specimens in 

 Essig 's collection. 



14. Genus Fullawaya Essig 

 Essig, Pom. Jour. Ent., vol. 4, p. 735, 1912. Type F. saliciradicis n.sp. 



31. Fullawaya saliciradicis Essig 



Figure 75 



Essig, Pom. Jour. Ent., vol. 4, p. 737, 1912 (orig. desc.). 

 Eecord. Salix laevigata, Santa Paula, August, 1911 (Essig). 



On the roots of Mallow near Santa Paula, Essig once found a large 

 number of aphids, the greater part of which were apterae, although 

 a few alates were present. Unable to identify them with any known 

 species, or to fit them into any genus, he described them as this species. 

 Since then they have not been taken. The author has had access to 

 cotype specimens in Essig 's collection. 



15. Genus Thomasia Wilson 



Wilson, Can. Ent., vol. 42, p. 386, 1910. Type Chaitophorus populicola Thomas. 



This genus is separated from Chaitophorus principally by the 

 comparative lengths of the antennae and the comparative lengths of 

 the spur of the sixth antennal segment. In Chaitophorus (type Aphis 

 aceris Linn.) the antennae are almost as long as the body, and the 

 spur of the sixth segment is over five times as long as the base. In 

 this genus the antennae are but about one-half as long as the body, 

 and VI spur is but slightly longer than VI base. 



