THE STATE ENTOMOLOGIST, (55 



yard that never showed signs of the disease before, except on the hypothesis 

 of the winged insect having flown there and stai'ted the colony. 



We have alreadj^ seen that certain individuals of the root-inlml>iting 

 type become winged. Why these individuals become winged while others 

 never do, is, perhaps, not for us to understand. Signoret ventures the La- 

 marekian suggestion that the need of quitting roots that are already de- 

 stroyed may be one reason, and the pupffi are certainly found more particu- 

 larly on badly infested roots. All plant-lice multii^ly agamically during the 

 summer months while they are abundantly nourished, but towards winter 

 when, by this mode of reproduction, and by the diminishing nutriment in 

 the dying foliage, the lice become, so to speak, exhausted, then lo and be- 

 hold winged males and females appear! Numerous other fiicts in insect life, 

 such as the j)i'oduction of drone bees solely from unfertilized eggs, etc., indi- 

 cate that the winged male may be, in some way or other, connected with defect- 

 ive vitality; and Mr. Thomas Meehan, of the Gardeners' Monthly, has so fre- 

 quently observed such to be the case with jjlants, that he considers it a law 

 "that with a weakened vitality comes an increased power to bear male flow- 

 ers."* But this throws no light on the production of winged females, and 

 here, as in thousands of other instances, nature tells us plainly to be sat- 

 isfied with the facts without the exjjlanation. 



Our winged female is a reality ! What, then, are her functions? In 

 the breeding jars she invariably flies towards the greatest light, and her large 

 compound eyes, and ample wings indicate that she was made for the light 

 and the air. We have also seen that she is burdened with two or three eggs 

 only, and m}^ opinion is that after meeting her mate, her sole life duty is to 

 fly off' and consign her few eggs to some grape-vine or grape-bud, and that the 

 lice hatching from these eggs constitute the first gall-producing mothers. 



I am led to this opinion by the fact that about the middle of May,* in 

 looking for the galls, I always find but two or three to a vine, and general- 

 ly but one to a leaf. These vernal galls — as one would expect from the 

 greater vitalit}^ of the young from fertilized eggs, and the greater succulency 

 of the leaves at that season — are much larger than the ordinaiy summer 

 form, and generally have a decidedly rosy tint on one side. Similar galls 

 have also been found in France. Just as many other insects prefer certain 

 species of j)lants, or even certain varieties of a species, so our winged Phyl- 

 loxera shows her preference for the Clinton and its close allies. She occa- 

 sionally deposits her eggs on other varieties, as I have found the large ver- 

 nal galls on Concord, Hartford Prolific, etc., and it follows that she must 

 do so where no riparia vines occur. But, except on the varieties of the 

 latter species, the young lice hatching from her eggs do not seem to be 

 capable of forming galls, on the leaves, but make straightway for the roots. 

 Only in this manner can we account for the galls abounding so much more 

 on some varieties than on others. 



Some persons may wonder how a minute insect with such delicate 

 wings, braced with so few simple veins, as those possessed b}' our Phylloxera 



*Proc. Am. Ass. Adv. Sci., 1869, r. ^')(;. 



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