THE PLUM. 



AFFECTING THE LEAVES. 



"Wriakling and distorting the leaves; a black, shining plant-louse, with a pal 

 green abdomen. 



The Plum Leaf-iousk, ^phis Prunifolia:. 



The Aphis which infests the under sides of the leaves of our 

 native and also our cultivated plums, curling and distorting 

 them, is one of the most variable species which I have met with 

 pertaining to this family. And so much does it disagree with the 

 accounts which we have of the plum louse of Europe {Jiphis 

 Pruni, Fab.) that I am constrained, though with some doubt, to 

 record it as a distinct species. The descriptions given of the 

 plum louse are quite discordant. Walker (List of British Mu- 

 seum, p. 989) describes the viviparous winged female as dark 

 gray with nectaries hardly projecting above the surface of the 

 abdomen, whereas, in all the winged individuals of our American 

 insect which have fallen under my observation, the nectaries are 

 cylindric, nearly or quite equalling the tip of the abdomen. It 

 further disagrees with his description, in having the third vein 

 of the fore wings not much further from the second at tip than at 

 base, and the fourth vein strongly instead, of slightly curved. 

 Fabricius (Ent. Syst. iv. 213) describes the European insect as 

 having a greenish hody, antennae and legs, with a darker abdo- 

 minal stripe and point each side of the base, and the margin 

 plaited. Unless this description is very faulty our plum louse 

 must be distinct, it having the thorax and antennse uniformly 

 black, and no plication on the sides of the abdomen; nor can the 

 large dusky spot be termed a stripe. Since the foregoing was 

 written I notice that M. Amyot (Annals Entom. Soc. 2d series v. 

 476,) gives the fop of the head and the thorax of the plum aphis 

 as brown and dusted with a white powder. This more strongly 



