Green-Fly. 



229 



winter, hale hill spring, and produce imperfect females. A lew^ of these may become 

 winged, and a few may he males ; but these exceptions are not so numerous as 

 to prevent our speaking of this generation being composed of imperfect and wingless 

 females. In from ten to twenty days these imperfect females begin to produce — 

 not eggs, but living young, and continue producing them at the rate of from three 

 to seven per day. These young in turn, after two or three weeks, likewise produce 

 living \-oung, and the same process may be repeated in successive generations 

 until the autumn. Some of these generations may be winged, following upon 

 a fallmg off in the supply of nutriment. The wings enable the individuals to migrate 

 to some other species of food-plant richer m sap, from wliich after several months 

 they may return to plants of the original species, and there produce a generation 

 that is sexually perfect, and that lays fertile eggs. These sexually perfect green-fly 

 are smaller than the imperfect individuals ; the females are always wingless, and the 



_/.'i / . ( arrerui. 



Subterranean Green-Fly. 



Several species live almost entirely uiukrground, where they feed upon roots, and are attended by ants for the sake ol their sweet 

 excretions. The ants take charge of the eggs in winter, and in spring plant out the young aphids in suitable places. 



males often so, though usually winged. It is remarkable that there are no fewer 

 than three distinct types of males, of which one has wings, and the other two liave 

 none. The wmgless males are distinct by reason of one possessing a mouth, whilst 

 the other is without one. 



One might imagine that with an Insect so generally abundant in temperate 

 climes everything in relation to its structure and habits would have been ascertained, 

 and made widely known many years ago ; but at least one fact over which many 

 generations of observers have erred has only been set right within recent years ; 

 the error, however, still makes its appearance in print from time to time. This 

 is in reference to the source of the honey-dew% which makes the green-fly so desirable 

 to ants as a kind of milch-cow. Most species of green-fly — not all — possess a pair 

 of siphons which jut out from the upper side of the fifth segment of the hind-body. 

 From these siphons are produced globules of an oil-like matter, which is really 



