STATE AGRICULTURAL SOCIETY. 208 



the loosened earth, and hiter through the unmolested soil, continued 

 up to the present time. 



The insect in various stages of development could be found in the 

 earth from the surface to the roots, the most incomplete foi'ms being 

 found deepest below the surface of the ground. Some were found 

 under stones, and in such positions as to place it beyond a doubt tbat 

 they passed thi'ough the changes underground, and came to the sur- 

 face in a transformed condition, contrary to the accepted belief of a 

 transformation at the surface of the ground. 



A peculiar circumstance was noticed on the twentieth of August, in 

 the appearance of a large number of larvae upon the surface of the 

 ground. They were found as much as two feet from the stock, and 

 from three to twelve inches from the fine roots, as well as tlirough the 

 soil to the roots. The significance of their appearing in this manner 

 can be appreciated when we learn that they crawl upon bits of rub- 

 bish, sticks, leaves, etc., upon the spot, and even take kindly to grow- 

 ing canes placed in their way. 



Up to August twenty-sixth no specimens of the gall louse, or leaf- 

 inhabiting form of the phjdloxera, had been identified at the Univer- 

 sity or elsewhere in California, so far as known. At this time the 

 fresh young leaves near the ends of three canes, which stretch from a 

 " Canada" vine toward the infected stock, bore a few peculiarly formed 

 galls, containing egg-laying mother-lice as well as eggs, and numerous 

 larva). A few isolated and abandoned ones were also found on the 

 old leaves nearer the stock of the vine. It thus seemed probable that 

 the root-inhabiting form had here changed its habit toward that of 

 the gall louse, a point still held in dispute by the French scientists. 



An attempt was therefore made to produce more galls upon the 

 foliage of the '' Canada" vine by infecting it with larvte from the roots 

 of the adjoining infested stock. A cane was led from the opposite 

 side of the resistant vine, and its terminal leaves fastened to an 

 infested spot of soil. The leaves and part of the canes were soon cov- 

 ered with young larvae, and a few quiet winged insects; the former 

 passing freely about upon the leaves, but forming no galls, or at least, 

 only doubtful and abortive attempts. Some of the young leaves upon 

 the infected canes were pierced by young larva3 which had settled 

 just outside of the fresh galls, and had remained until a red dead spot 

 had been formed. Others of the larvte were seen crawling about; 

 but they did not readily establish galls. Contrary to the usual habit 

 of the gall louse, they kept mostly upon the under side of the leaf. It 

 thus appears that at least so late in the season, the change of habit 

 from root to leaf is not readily made. 



Of tlie known enemies to the j^^ylloxera, only two forms were identi- 

 fied during our observations. The ■pliylloxera thrips were seen passing 

 about in considerable numbers upon the leaves and some even came 

 from the galls, many of which they had cleared of their inhabitants. 

 A few specimens of the tyroglyphus, ov phylloxera mite appeared among 

 the winged insects that were taken from the "trap;" they were also 

 found upon the roots of adjoining vines. It is, therefore, probable 

 that its usual enemies have accompanied the phylloxera to California. 



Several practically important conclusions result from the above 

 observations. It appears that the light Summer rains of the season 

 have favored to an extraordinary degree the development and activity 

 of the pest, especially of its winged form, most dangerous as the carrier 

 of infection; and that this form was developed through the months 



