APHIDS INJURIOUS TO ORCHARD FRUITS. 25 



THE CHOKECHERRY APHIS.^ 



The chokecherry aphis is found, abundantly upon chokecherries and 

 related trees. It is a pale green insect and is conspicuously mealy. 

 The winged forms have a black head and body. 



The feeding habits of this species are very similar to those of the 

 black cherry aphis. The leaves of the terminal twigs are attacked 

 and twisted by the feeding of the insects, entire twigs sometimes be- 

 ing destroyed. 



As in the case of the black cherry aphis, the eggs of this insect are 

 laid on the cherry twigs. After the stem-mothers have become ma- 

 ture and produced young, these latter crowd the terminal leaves. 

 Winged forms are produced during early summer, and by midsum- 

 mer the insects usually have disappeared from the trees. Their 

 summer host is not known, but in the fall migrants return to the 

 cherry trees to deposit the egg-laying females. 



PEACH APHIDS. 



THE GREEN PEACH AFHIS.^ 



The green peach aphis is a common form upon peach trees. The 

 stem-mothers in spring, as well as the fall egg-laying females, are 



Fig. 18. — The green peach aphis (Rhopalosiplmm pcrslcac) : Colony on underside of 

 peach leaves. Much enlarged. (Original.) 



often pinkish, and at other times light green. The wingless agamic 

 form also is light green, while the winged individuals have a black 

 head and body and a large dark-brown patch on the abdomen. This 

 marking occurs upon both the spring migrant and the fall migrant. 

 They are similar in other respects excepting that the fall form has 

 the honey tubes somewhat swollen. 



On the peach this species feeds entirely upon the leaves, on which 

 the insects may be found in large numbers crowded on the under- 

 side. (Fig. 18.) It has a large number of other food plants, in- 

 cluding numerous garden vegetables. 



^Aphis cerasifoliae Fitch. -Rhopalosiplmm pcrsicae (Sula.). 



