294 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



pea-green color, light brownish between the wings and on the head, 

 the eyes are red, and the legs, antennae and honey tubes are yellow- 

 ish, tipped with black. The wingless females are similar in size and 

 color, but are much broader across the abdomen, and the honey 

 tubes are somewhat larger. The mouth-parts of the pea-aphis are 

 of the sucking type, and it secures its food by puncturing and suck- 

 ing up the juices of the plant. The plant is thus injured by the 

 large number of aphids sucking out its juices and causing it to 

 wilt and die. 



Life History. The aphids pass the winter on clover and 

 vetches, and often increase upon clover so as to do it serious 



injury. Where peas are 

 available the winged 

 females usually migrate 

 to them about the time 

 peas are 6 or 8 inches 

 high, and give birth to 

 live young, which de- 

 velop into wingless vivi- 

 parous females. These 

 females, as do those of 

 subsequent broods 

 throughout the summer, 

 give birth to live young, 

 and reproduction goes 

 on at a rapid rate. Ac- 

 cording to the observa- 

 tions of Mr. R. L. Web- 

 ster, in central Illinois, 

 an aphid becomes 



FIG. 251.-The pea-aphids on stems of red clov- g rown about eleven 

 er natural size. (After Folsom.) days after it is born, 



lives about twenty-five days and gives birth to about fifty young, 

 though under favorable conditions over one hundred are frequent- 

 ly born. Sixteen generations have been observed from March 23d 

 to October 4th. Winged aphids develop as often as the food- 

 plant becomes overcrowded and it is necessary to migrate to 

 avoid starvation. 



