430 Agricultural Experiment Station, Ithaca, N. Y. 



is shown in Fig. 2; the lines beneath the figure represent the 

 natural size of this fonn. 



In its younger stages the insect resembles the adult, but is 

 lighter in color. All the forms thus far observed are females; 

 often plant-lice breed freely for many genera* ions or even yfai^^ 

 without the appearance of males, nothing but the igamio females 

 being produced. 



The life history of the insect. — Plant-lice present more varied, 

 peculiar and interesting phases in their life histories than do n^oet 

 other insects. The mother is often viviparous; that is, she brings 

 forth her young alive ; the little louse may be sc^en kicking i o free 

 itself from the mother who is perhaps calmly walking about or 

 feeding. Many generations of these agamic females may be pro- 

 duced in succession, and it requires only eight or ten days for a 

 generation. .:\nd further, as one mother may give birth to 1 00 

 young at the rate of four or five a day it is easy to see vith 

 what astonishing rapidity these insects may often multiply. 



The Black Peach Aphis breeds thus agamicallv all the year 

 round, and no eggs nor males have been found. Only the wing- 

 less forms occur upon the roots where they breed freely and are 

 to be found at all seasons of the year, often a foot or more benf ath 

 the surface even in stiff clay soils; sandy soils are, however, pre 

 ferred by the pest. 



Early in spring, as soon as the buds begin to swell, some of 

 these root forms make their way to the surface and to the 

 branches. Here the winged form develops and flying to new 

 quarters founds others colonies, thus spreading the pest. Thtfee 

 branch forms are the most numerous from April to July. About 

 mid-summer most of these make their way to the ground and to 

 the roots. Usually a few specimens remain on the leaves through- 

 out the summer and autumn and even through the winter. Our 

 correspondent in Niagara county wrote us, November twenty- 

 fourth, that, although it had frozen hard twice, tlu^ aphids were 

 as lively as ever on the branches. These individuals which thus 

 hibernate upon the branches with those .vhlch *ome from the 

 ground form the nucleus for the early spring broods. 



This pest is often accompanied by a small yellow ant which 

 has been seen transporting the aphids to places of safety. It is 



