﻿OF THE STATE ENTOMOLOGIST. 15T 



THE GRAPE PHYLLOXERA. 



This insect still continues to attract much attention abroad as 

 well as at home. Owing to the excessively wet summer of 1875 it did 

 comparatively little injury in our own vineyards, and I have little to 

 add to what has been previously published in these Reports. 



COMPLETION OF ITS NATURAL HISTORY. 



Having shown last year that our knowledge of the natural history 

 of this insect was then all but completed, it gives me pleasure to now 

 record its completion, which I can best do by supplementing with a 

 few additional notes the following paper read last October before the 

 St. Louis Academy of Science : 



It is well known to those who have followed the habits of Phylloxera vastatrix, as- 

 these have been discovered and recorded, that one of the most important points in the 

 life-history of this insect that has hitherto remained unsettled, is the nidus which the 

 winged female chooses for the consignment of the few eggs she lays. In 1871 1 ven- 

 tured the supposition that these eggs were deposited in the down of the leaf-buds,* but 

 subsequent observation led me to believe that " the more tomentose portions of the 

 vine, such as the bud, or the base of a leaf-stem, furnish the most appropriate and de- 

 sirable nidi''' for these winged mothers, and that the eggs were also laid in minute cre- 

 vices on the surface of the ground, especially around the base of the vine f— all these 

 conclusions being based on observations made on the insects in confinement. The 

 question is an important one practically, as the hope was entertained that, by knowing 

 just where to look for these eggs, we might be able to check the rapid spread of the 

 Phylloxera disease, since it is through them alone that the disease can be started in 

 new localities distant from infested regions. Feeling, from past experience, that it was 

 extremely difficult to solve the problem in the open vineyard, and that experiments 

 with the insect confined in tubes were more or less unsatisfactory, I built, early in Sep- 

 tember, a tight house of heavy Bwiss muslin, six feet high and four feet square, over a 

 Clinton vine. The house was built so as not to permit even so small an insect as the 

 winged Phylloxera to get in or out, and the vine was trimmed so that but few 

 branches and leaves remained to be examined. Into this enclosure I brought an abund- 

 ance of infested roots, and for the past five or six weeks I have been getting the winged 

 females confined where 1 could watch their waj's. In addition, I prepared large, wide- 

 mouthed glass jars, by half filling with moist earth. Into the earth was then stuck a 

 vial of water holding a tender grape-sprig with young leaves. The leaves were thus 

 easQy kept fresh and growing for a fortnight and upward. From day to day, as the 

 winged females were obtained from other vessels prepared for the purpose with infested 

 . roots, they were introduced into these jars containing living leaves. 



The results of these endeavors to supply the winged mothers as nearly as possible 

 with the natural conditions have been satisfactory, and they prove that, as was sur- 

 mised, the eggs are laid in crevices of the ground around the base of the vine, but still 

 more often on the leaves, attached generally by one end amid the natural pubescence, or 

 rather down, of the under surface ; and while heretofore all efforts to artificially hatch 



* Fourth Mo. Ent. Rep., p. 65. t Seventh Mo. Ent. Rep., p. 98. 



