INSECTS INJURIOUS TO MELONS, CUCUMBERS, ETC. 345 



form is about one-fifteenth inch long and varies from light yellow 

 or tan colored to deep olive-green or deep green which appears 

 almost blackish, the abdomen being always more or less mottled. 

 The rather long, tapering honey-tubes are jet-black, and the legs 

 and antennae pale whitish-yellow. The young nymphs always 

 show a distinct yellowish-brown or pale salmon-colored area just 

 in front of the honey-tubes and a dark transverse band between 

 them. The nymphs of the last stage, in which the wing pads are 

 visible, are marked on the back with little flecks of silvery white, 

 waxy bloom. The winged female is about the same length and the 

 wings expand one-fifth to one-quarter inch. The color varies as 

 in the wingless form, but there are black spots along the sides 

 of the abdomen, and the head and thorax are dark as shown in 

 the above figure. 



The melon-aphis is found throughout the country southward 

 through Central America, and though it often does serious damage 

 in the North it is worse in the South. It has a long list of food 

 plants, among the crops injured by it being all the cucurbs, cotton, 

 okra, orange, and its occasional food-plants include many others, 

 as it is found on a long list of weeds, most abundantly on shep- 

 herd's purse and pepper-grass, upon which it multiplies in early 

 spring and probably passes the winter. 



Life History. The life history is much the same as that of most 

 of our common aphids, though of some phases we are still in 

 ignorance in spite of the most careful study. The females give 

 birth to from four to ten aphids a day, depending upon the tem- 

 perature and food supply, and these become full grown in from six 

 to eight days. As the affected leaf becomes non-succulent the 

 aphids migrate to another leaf and often cluster on the terminal 

 which is checked and stunted. As they become more numerous, 

 winged forms migrate to other plants and within two weeks a 

 colony of fifty or more will form the progeny of every one born 

 by the immigrating female. Reproduction seems to go on this 

 way throughout the year, being stopped only by the cold of win- 

 ter, as far as has been observed. No true sexual forms or eggs, as 

 are known to occur with other nearly related species, have been 

 observed, and the viviparous forms have been found throughout 

 the winter in Colorado and Texas. 



