12 Farmers’ Bulletin 1128. 
THE CLOVER APHIS.! 
The clover aphis, first found injurious to the apple in Colorado, 
is now known to occur abundantly in some regions in the East. It 
attacks the apple in a way similar to the green apple aphis, but since 
there is a considerable migration of individuals to clover, it is less 
abundant on the apple in summer than the latter species. Thestem- 
mothers of the clover aphis are pink and the individuals of the next 
generation are yellowish green, The winged forms have a large black 
patch on the abdomen and in this way resemble the migrants of the 
rosy aphis. The two species, however, can be distinguished readily 
by the length of the honey tubes. In the rosy aphis these are very 
long, while in the clover aphis they are short. The forms of this 
species which live on clover are pink. (Fig. 7.) 
SEASONAL HISTORY. 
The eggs of the clover aphis are laid upon 
the apple in much the same manner as those 
of the species already mentioned. The stem- 
mothers, which are hatched considerably earlier 
than those of the rosy aphis and the green apple 
aphis, give birth to winged and wingless forms, 
which in turn produce young, some of which 
become winged, while the others remain wing- 
less. As a rule most of the insects have be- 
come winged by early summer, although some 
wingless colonies occur during the summer on 
apple. These winged forms fly to clovers, and 
settling upon the stems produce wingless young. 
t sete ec ee These and succeeding generations, which may 
of apple tree. Much en- contain winged individuals, pass down to the 
ieee crown of the clover plants, and here the species 
lives throughout thesummer. During October numerous fall migrants 
are produced upon the clovers and fly to the apple, where they give 
birth to the young egg-laying females. Winged males produced upon 
the clovers follow the fall migrants to the apple, and here mate with 
the females, which later deposit their eggs. 
1A nuraphis bakeri (Cowan). 
DESCRIPTION OF PLATE IV. 
Tur APPLE-GRAIN APHIS: A, Opening apple bud in spring infested with young aphids. The empty 
egg shells are seen still adhering to the twig; B, young aphids, more enlarged; C, the leaves unfolding 
in the bud; D, infested blossoms; JZ, a full-grown aphid of the first generation from the blossoms (D); 
F, a winged aphid, or spring migrant, from the next generation on the apple leaves; G, flight of spring 
migrants from apple to grain (H); H, oats infested by summer generations cf aphids which are mostly 
wingless; J, wingless summer form; J, flight of fall migrants and males from grain back to the apple ( XK); 
K, fall migrants and males alighting on apple leaves, the fall migrants giving birth to the sexual females; 
L, afall migrant; M,a male produced on apple in fall; NV, sexual females showing extreme color varieties, 
and eggs which are pale when laid, but later turn black; O, wingless aphids that remain about the roots 
of the grain when the winter is not too severe. 
