1869.1 NEW VINE DISEASE. 203 



an article which M. J. E. Planchon contributed a short time ago to the * Comptes- 

 Rendus de I'lnstitut' (1868, p. 588). Here is the passage from the 'Revue' : — 



"I will here give a brief resume of all I learnt about the habits of the 

 Phylloxera vastatrix from a series of observations made on the spot, in three 

 short visits to the south of France ; also all I noticed with reference to the 

 specimens which I kept in glass bottles during forty consecutive days. 



"Its best-known form is that in which no trace of wings can be discovered. 

 When the insect is about to lay its eggs (that is, in its adult female state), it 

 forms a small ovoid mass, having its inferior surface flattened, its dorsal surface 

 convex, being surrounded by a kind of fillet, which is very narrow when it 

 touches the thoracic part of its body, which (formed by five rather indistinct rings) 

 is hardly separated from its abdominal part of seven rings. 



' ' Six rows of small blunt tubercles form a slight protuberance on the thoracic 

 segments, and are found very faintly marked on the abdominal segments. 

 The head is always concealed by the anterior protuberance of the buckler ; the 

 antennae are almost always inactive. The abdomen, often short and contracted, 

 becomes elongated towards laying-time, and there can be easily seen one, two, or 

 sometimes three eggs, in a more or less mature state. 



" The egg sometimes retains its yellow colour for one, two, or three days after 

 it has been laid ; more often, however, it changes to a dull-grey hue. From five 

 to eight days generally elapse before it is hatched. The duration of this period 

 depends a good deal on the temperature. The quantity of eggs, and the rapidity 

 with which they are produced, are probably determined by a variety of circum- 

 stances — the health of the insect, the quantity of nourishment it is able to obtain, 

 the weather, and perhaps other causes. A female which had produced six eggs at 

 eight o'clock a.m. on the 20th of August, had fifteen on the 21st at four p.m. — 

 that is, she laid nine in thirty-two hours. Other females lay one, two, or three 

 eggs iu twenty-four hours. The maximum quantity is thirty in five days. The 

 eggs are generally piled up near the mother without any apparent order, but 

 she sometimes changes her position so as to scatter them all around her. They 

 have a smooth surface, and adhere lightly to each other by means of a slimy 

 matter which attaches to them. 



" Hatching takes place through an irregular and often lateral rent in the egg^ 

 the empty and crumpled membrane being found among the other eggs in 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 fur a favourable situation. Their movements are more rapid 

 than those of adults. They appear to inspect, as it were, with their antennge the 

 surface they travel over. The movements of the antennae are generally alterna- 

 tive, 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 ofi" 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 



