WINE-MAKING IN CALIFORNIA. 49 



A newly developed winged insect was taken from a moist 

 bottle and placed upon a glass plate, where she soon made 

 attempts to fly. Her wet wings were repeatedly brought per- 

 pendicularly over her back and rubbed together, apparently 

 to free them from moisture, and then she attempted to leap, 

 or fly, often raising, by a peculiar curve, from two to six 

 inches high. With the last attempt she flew away. 



Roots Producing the Winged Form. -The vigorous, bushy, 

 fibrous growth, or network of root< around the tap-root, evi- 

 dently caused by manuring and moisture, seemed best to ful- 

 fill the necessary conditions for the development of the winged 

 females. It was later shown that these fibrous *oots were 

 specially productive of this form; in fact, it is very seldom 

 that it is found on other roots. 



Conditions of their Development Invasion of 1884. Here 

 it may be well to suggest as a possible explanation for the 

 greater production of the winged form in France, that the 

 more thorough fertilization of the vineyards in that country 

 has favored a more general growth of the suiface roots upon 

 which the winged form is mainly produced ; also, that the 

 late spring and summer rains bring about a similar condition 

 of growth. The summer rains alone of France, which last 

 far into August and September, would be quite sufficient to 

 produce surface roots of the kind required to produce winged 

 insects in great abundance. It is just previous to this time 

 that the winged invasion occurs, when the insect is carried 

 in swarms to adjacent vineyards. This is a point which I 

 believe has never been suggested, and the truth of which 

 seems to be supported by experience in this State, for neither 

 of the conditions spoken of is ordinarily realized to any ex- 

 tent in California. But the unusual summer rains that oc- 

 curred in 1884, and which were followed by such a great 

 general development of insect pests in 1885, seemed to im- 

 part also to that of the winged phylloxera, a similar impetus ; 



