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 green 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 abdo- 

 men 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 « green 

 bh 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 0.06 in length by 0.03 in width. 



The "Winged PujM.LEAF-LorsE 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 abdomen acuminate; 

 nectaries cylindric, equalling the tip. The legs are pale yellowish, the tips of the 

 thighs and the feet dusky or black. The antennas are black, their bases pallid. Th 

 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 indi- 

 vidual occurs having them normal 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 individn. 

 als of this species: 



u. Abdomen above deep black and shining. 



6. 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. 



