THE GRAPE VINE. 121 



rent in tlie egg, the empty and crtunpled membrane being fonnd 

 among the other eggs ia different stages of hatching. 



" During the first period of their active life — two, three, four, 

 or five days, as the case may be — ^the insects are in an erratic 

 state. They creep about as if they were seeking for a favourable 

 situation. Their movements are more rapid than those of adults. 

 They appear to inspect, as it were, vrith their antennse, the sur- 

 face they travel over. The movements of the antennse are 

 generally alternative, and, if the comparison may be pardoned, 

 are not unlike the two sticks of a blind man, which he uses to 

 explore the ground he is about to tread. 



" After a few days of this errant life, the young insects seem to 

 fix upon a spot to settle in. Most frequently this is a fissure in 

 the bark of a vine, where their suckers can be easily plunged into 

 the cellular tissue, full of saccharine matter. If you make a 

 fresh wound on the root by cutting off a little piece of the bark, 

 you may see the pucerons range themselves in rows around the 

 wound, and, once fixed, they apply to the root their antennae, 

 which appear like two small divergent horns. At this period of 

 their life, about the 13th or 14th day after their birth, they are 

 more or less sedentary ; but they change their places if a new 

 wound is made on the root, which promises a fresh supply of food. 



"What sense is this which directs these subterraneous pucerons 

 towards the place which is most suitable for them ? It cannot 

 be sight, as their eyes are merely coloured spots, and they creep 

 as if they were blind. It cannot be hearing, because they seek 

 no prey but a vegetable tissue. It is probably the sense of 

 smelling ; and one may. well ask if the nuclei which appear 

 enshrined in the last articulations of the antennse are not the 

 organs of this function, the seat of which has been so much dis- 

 puted? Among these non- adult insects, attached by their 

 suckers to the vine-root, are seen, here and there, some of 

 middle size. Their colour is a deeper orange, the abdomen 

 shorter and more squarely formed. These individuals are more 

 sedentary than the others. I have sometimes imagined they 

 might be wingless (apterous) males of the species ; but as nothing 

 has happened to confirm this very problematical hypothesis, and 

 as I have seen undoubted females much resembling these ex- 

 amples in colour and form, I incline to the belief that there are 

 no sexual differences among them, A kind of double moult pre- 

 cedes the adult state. The first takes place shortly after birth. 



