270 SCHOOL ENTOMOLOGY 



the plants. They pass the winter on clover and vetches, 

 sometimes becoming so numerous as to do serious injury. 

 The winged females migrate to the peas about the time they 

 are six to eight inches high, and give birth to young which 

 develop into wingless, viviparous females. Both wingless and 

 winged females occur throughout the season, the latter pre- 

 dominating whenever food becomes scarce. The winged 

 forms are about one-eighth of an inch long with wings ex- 

 panding two-fifths of an inch. The body 

 is a pea-green color, the eyes are red, and 



fthe legs, antennae and honey-tubes are 

 yellowish tipped with black. The wing- 

 less females are similar, but somewhat 

 broader. A female becomes grown in 

 FIG. 192. The pea- about e i even days after birth, lives about 

 aphis (Macrosi- 

 phum pisi Kalt). twenty-five days, and bears about 50 



Winged and wing- young, though sometimes 100 are born. 



less viviparous Sixteen generations have been observed 



young enlarged, between March 23d and October 4th in 



Central Illinois. The best means of 



avoiding injury by this species is to grow early varieties. 



Brushing the aphides from the vines with a pine branch and 



following with a cultivator, will destroy many of them on a 



hot summer day. 



Melon Aphis * (8). The melon aphis may be found on 

 various weeds such as shepherd's purse and pepper grass in 

 early spring and on melons and other cucurbs soon after 

 they start growth. If allowed to multiply unchecked it will 

 often become so abundant as to ruin a crop just as the melons 

 are commencing to ripen. The wingless females are about 

 one-fifteenth of an inch long, varying in color from light yel- 

 low or tan to olive or deep green, appearing almost blackish; 

 * Aphis gossypii Glover. 



