PLUM. LEAVES — PLUM LEAF-LOUSE. 123 



indicates the European species to be distinct from ours, which 

 has a smooth shining thorax not in the least coated with any 

 meal-like matter. 



This aphis is much less common than those which pertain to 

 our other fruit trees. Its generation and habits are so similar to 

 those of the Apple plant louse, that a separate account would be 

 little more than a repetition of what has already been related. 

 It only remains, therefore, to give a description of this species 

 in its larva and its perfect states. 



The Larva when first hatched is of a white color, the body slightly tinged 

 with green, the feet, tip of the beak and eyes black. As it increases in size 

 three stripes of a deeper gre.en begin to appear and become more distinct and 

 are finally of a bright green color. One of these stripes extends along each 

 side of the thorax and abdomen, and has in it on the thorax a large deep green 

 dot, and upon the abdomen two or three less deeply colored dots; the third 

 stripe is on the middle of the abdomen and is not extended to the thorax. The 

 body has now become of a greenish white color, the legs, nectaries, antennae 

 and beak white, without any tint of green, and somewhat pellucid. The tip 

 of the beak, the ends of the feet and the eyes are black. It is of an oval form, 

 and measures 0.0G in length, by 0.03 in width. 



The W"in t ged Plum Leap-louse is 0.14 long to the tip of its wings. It is 

 black and shining, its abdomen pale green with a black dot on each side of the 

 middle of the two or three anterior segments, a large dusky spot rather behind 

 the middle, and a short dusky band between this and the base; tip of the ab- 

 domen acuminate; nectaries cylindric, equalling the tip. The legs are pale yel- 

 lowish, the tips of the thighs and the feet dusky or black. The antennas are 

 black, their bases pallid. The wings are pellucid, their veins slender, blackish, 

 the rib-vein and base of the third vein pallid ; inner margin with a black line 

 extending inwards from the apex of the first vein. The veins are analogous to 

 those of A Pruni in their relative distances, except as already noticed; they, 

 however, vary so much that it is seldom an individual occurs having them nor- 

 mal in both wings. The third vein is as near the second at its apex as at its 

 base, oftener than it is more distant. 



The following are some of the varieties which may be met with among in- 

 dividuals of this species : 



a. Abdomen above deep black and shining. 



b. Abdomen pallid whitish; tips of the thighs and veins of the wings 



dusky, not black. 



c. First fork at tip as far from the tip of the second fork as from the third 



vein. 



d. First fork at tip much farther from the tip of the second fork than from 



the third vein, the cell between the first fork and third vein narrower 

 at its base. 



