Mr. F. Walker's Descriptions 0/ Aphides. 43 VIII. — Descriptions 0/ Aphides. By Francis Walker, F.L.S. [Continued from vol. ii. p. 431.] 56. Aphis dirhoda, 11. s. This species feeds on the rose with Aphis Rosa, and is some-times far more numerous than that species in the spring and in the autumn, but its appearance is less regular ; it frequents various species of rose both wild and cultivated, such as Rosa centifolia, R. canina, R. eglanteria ; and in the summer it migrates to dif-ferent species of corn and of grass {Secale, Triticum, Avena, Ho?--deum, Bromus, Dactylis, Holcus, and Poa), and it fixes itself on the blades of these plants, whereas^. Avenae prefers the flowers. Aphidius Avena, an Allotria, Asaphes anea, and Megaspilus Car-penteri, are its parasites, and these will be more particularly noticed in another part of these descriptions. The viviparous wingless female. This sometimes rests through a severe winter under the rose-leaves without being injured, and begins to multiply very early in the spring : it is oval, and pale greenish yellow : the feelers have pale brown tips, and are about one-fourth of the length of the body : the eyes are dark red : the mouth and the nectaries are pale yellow with brown tips, and the latter are about one-sixth of the length of the body : the tip of the abdomen is brown : the legs are shorter and more slender than those of Aphis Rosa, and the feet are pale brown : it is also distinguished from that species by its paler colom-, its shorter feelers, and its larger body ; the two kinds may often be seen together on one rose-twig, each surrounded by its respective little ones. The front is prominent in the middle between the eyes : the tubercles on w^hich the feelers are seated are rather less developed than those of the preceding species ; the fourth joint of the feelers is much shorter than the third; the fifth is shorter than the fourth ; the sixth is not half the length of the fifth ; the seventh is nearly as long as the third. The viviparous winged female. While a pupa it much resembles the wingless female in colour : its wings are unfolded in April or May, and then it is pale green : the chest is bufi" ; its lobes are pale brown : the feelers are brown, green at the base, and much shorter than the body ; the fourth joint is shorter than the third, and the fifth is shorter than the fourth ; the sixth is nearly half the length of the fifth ; the seventh is a little shorter than the third : the eyes are dark brown : the mouth has a brown tip : the nectaries are about one-sixth of the length of the body : the legs arc pale yellowish green and rather long ; the feet and the tips of the thighs and of the shanks are brown : the wings are colourless.
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