152 FBUIT INSECTS 



darker colored than those on the apple, and have been described 

 as a different species, Aphis annuoe Oestlund. On the grasses 

 they lived on the blossom heads, but mostly on the stems, and 

 some of them at the base of plants. It has been suggested that 

 the species is biennial, the progeny of the spring migrants from 

 the apple living on grasses and grains until the autumn of the 

 second year before going back to the apple. 



Late in September we found many winged viviparous females 

 returning to the apple trees. These return migrants were very 

 similar to the spring migrating form, and soon gave birth to ovip- 

 arous females, which were wingless and of a yellowish-green or 

 dark green color. About the time these females matured, or three 

 or four weeks after the return migrant females came from the 

 grasses, there came to the trees the more slender, light greenish- 

 brown colored winged males. These males actively seek the wing- 

 less females, and we have seen them mate with the females of 

 the rosy apple aphis also. Egg-laying began late in October and 

 continued until December, the shiny black eggs being deposited 

 on the bark all over the tree, but mostly on the twigs near the 

 buds. The sexual forms may also appear on the pear, quince, 

 hawthorn or plum trees in autumn, and eggs be deposited thereon. 



All of the winged forms of this apple bud aphis, including the 

 summer broods on grasses, can be distinguished from those of 

 the other two species by the fact that the terminal fork of the 

 second vein behind the stigma is shorter and nearer the margin 

 of the wing. Usually the brownish coalescing spots around 

 the clavate cornicles are more distinct on all the forms of this 

 species. It leaves the tree for its summer food-plants so soon in 

 the spring that it does not curl the leaves as much as the other 

 two species. 



References 



Del. Agr. Exp. Sta. 13th Kept., pp. 137-149. 1902. 

 U. S. Bur. Ent. Circ. 81. 1907. 



