THE INSECTS OF NEW JERSEY. 117 



APHIS Linn. 



A. ambrosia Raf. On the various species of ragweed. 



A. asclepiadis Fitch. Occurs on various species of milkweeds. 



A. brassicae Linn. The common cabbage plant-louse. Occurs throughout 



the State and often in destructive numbers. 



A. cerasifoliae Fitch. Common on wild cherry in Hunterdon Co. (Sm). 

 A. cornifoliae Fitch. On the leaves of dogwood and "Cratsegus." 



A. gossypi Glover. The melon-plant louse: occurs throughout the State, 

 but much more commonly in the southern counties, where it often 

 destroys entire crops. It occurs also on a great variety of weedy 

 plants on which it passes the winter, migrating to the melon fields 

 in June. In ordinary seasons only a few hills in a field become in- 

 fested in that month, and from these the spread is in every direction. 

 Covering these hills with tight boxes, tubs or hay caps, and evap- 

 orating beneath them carbon bisulphide at the rate of 1 tablespoon- 

 ful to every cubic foot of space will often check the spread of the 

 species over the field and save the crop. Once they are generally 

 distributed the whale-oil soap is the only satisfactory remedy. 



A. forbesi Weed. The strawberry-root louse. Locally and seasonally 

 common in the light sandy soils of southern New Jersey, and rarely 

 injurious. In the more northern parts almost entirely absent. 



A. maidis Fitch. The corn-plant louse. Sometimes quite plentiful, but 

 not injurious in New Jersey. 



A. maidiradicis Forbes. The corn-root louse. A very destructive species 

 in the middle west, but in New Jersey of only occasional occurrence. 

 Found also on the roots of a variety of weedy plants and attended 

 by ants that care for the winter eggs and colonize the young on 

 proper plants in spring. 



A. mali Fabr. The apple-plant louse. Occurs throughout the State, some- 

 times in great numbers, causing serious injury. Spray very early 

 when this species is noticed in numbers, to kill off the stem-mothers 

 and their first brood before they cripple the leaves so as to serve as 

 shelters. "Malifoliee" is now considered a form of this species. 



A. persicae-niger E. F. Smith. The black-peach louse. Plentiful through- 

 out the State south of the Piedmont plain and most abundant in the 

 lighter sandy soils where the root form often does serious injury to 

 young trees. On the Piedmont plain and northward it is rare and 

 never injurious. Tobacco dust worked in a trench over the roots 

 around the tree is more or less satisfactorily used as a remedy. 



A. prunicola Kalt. Newark, Vineland (U S Ag) ; on plum. 

 A. prunifoliae Fitch. A widely-distributed species on plum. 

 A. quercifoliae Walsh. Feeds on oak, soft maple and button ball. 

 A. rumicis Linn. The bean-plant louse. Generally distributed, some- 

 times common, but never, in my experience, injurious in New Jersey. 



