130 INSECTS INJURIOUS TO STAPLE CROPS. 



eggs commence to hatch. The ants at once lay hare the 

 smartweed roots and carry their young wards to them, 

 where large colonies soon become established. 



Life-liidory — If the field is not planted in corn, the 

 lice will later feed upon the roots of the pigeon-grass or 

 purslane. About the first of May the second generation 

 of lice commences to appear, among them being both 

 winged and wingless forms. Like most j^lant-lice, this 

 brood, and all daring the summer, are produced by 

 females known as agamic females, without any intervention 

 of the male form, the young lice being borne directly by 

 the female without any Qgg stage. Such females are called 

 viviparous in contrast to those laying eggs, which are called 

 ovijDarous, and such a process is termed " budding '' or 

 partlienogenesis. The little brown ants again transfer the 

 lice to the roots of the young corn-plants about this time, 

 burroAving around the roots of the corn so as to lay them 

 bare, and even carrying hither winged lice. All through 

 the summer they attend the lice, burrowing around the 

 roots of the corn, and carrying them from plant to plant, 

 in return for which, upon stroking the lice with their 

 antennae, the lice give off the sweet " honey- dew" upon 

 which the ants feed; indeed, the lice have been well 

 likened to herds of cattle, cared for by the ant herds- 

 men. The first three generations each require about 

 nineteen days to become full-grown. During the summer 

 the lice continue breeding with extreme rapidity, the 

 broods becoming mature in an average of eleven days, , 

 some twelve broods occurring before the middle of Sep- 

 tember. During the summer both winged and wingless 

 agamic females occur, but about the middle of September 

 appears a brood of wingless lice including both true sexes. 



