Mr. P. Walker's Descriptions of Aphides. 45 



feelers is about half the length of the fifth ; the seventh is about 

 thrice the length of the sixth : the rib- vein begins to widen soon 

 after the middle of the length of the wing, and emits the fourth 

 vein near its tip ; the third vein is forked a little before one-third 

 of its length, and forked again just after two-thirds of its length. 

 Length of the body f-1 line ; of the wings 2^-3 lines. 



69. Aphis trirhoda, n. s. 



This species, which has a very quiet disposition, abounds on 

 the rose in the spring, and having acquired wings in May, it 

 emigrates thence to the columbine, where it feeds equally on the 

 upper surface and on the under surface of the leaf, which often 

 becomes red or purple from its injuries. It continues on that 

 plant till the end of October. 



The viviparous wingless female. It is elliptic, slightly convex, 

 not shining, whitish green, covered with a white bloom, and re- 

 markable for the peculiar softness and velvety appearance of its 

 skin : the front is straight : the feelers are white, and about half 

 the length of the body ; the first and the second joints are not 

 angular ; the fourth is less than half the length of the third ; the 

 fifth is shorter than the fourth ; the sixth is much shorter than 

 the fifth ; the seventh equals the fifth in length : the eyes are dark 

 brown : the mouth is white with a brown tip, and hardly reaches 

 the middle hips : the tip of the abdomen and the nectaries are 

 white, and the latter are one-twentieth of the length of the body : 

 the legs also are white. 



1st var. Pale yellowish green. 



2nd var. ? or a distinct species. The body is elliptical, convex, 

 dull, grass-green, with a very slight white bloom : the feelers are 

 brownish green, and about one-fifth of the length of the body : 

 the eyes are black : the mouth is dull green with a black tip, 

 and does not reach more than half way between the fore and the 

 middle legs : the nectaries do not rise above the surface of the 

 body : the legs are dark brownish green, and rather short. 



The viviparous winged female. This unfolds its wings at the 

 end of May : it is pale greenish yellow : the head and the discs 

 of the fore-chest, of the middle-chest and of the middle- 

 breast are black : there is a large black spot on each side of the 

 middle-chest : some short confluent black bands form a large 

 irregular spot on the disc of the abdomen, on each side of which 

 there is a row of black dots : the feelers are black, and a little 

 shorter than the body : the mouth is pale yellow ; its tip and the 

 eyes are black : the nectaries are pale yellow, and one-twentieth 

 of the length of the body; the third joint is rather stout; the 

 fourth is very slender, and less than half the length of the third ; 

 the fifth is a little shorter than the fourth, and the sixth than 



