﻿OF THE STATE ENTOMOLOGIST. 91 



the way by his remarkable biological studies of the European Oak 

 Phylloxera, made a year ago. It turns out, as was expected, that the 

 Grape Phylloxera agrees with its oak congener in producing wingless 

 and mouthless males and females; and the problematic winged indi- 

 viduals, with short bodies and relatively long wings and members, 

 which individuals were looked upon by myself and others as the 

 possible males, must necessarily be abnormal females.* The sexual 

 individuals have now been traced in the Oak and Grape species {guer- 

 cus and vastatrix) in Europe by Balbiani; and I have traced them 

 in three species { Riley i. vastatrix and what is probably carycBGaulis) 

 in this country. 



The life-history of the Grape Phylloxera may be thus epitomized: 

 It hibernates mostly as a younglarva(Rep.6, Fig. 5,) torpidly attached 

 to the roots, and so deepened in color as generally to be of a dull 

 brassy-brown, and, therefore, with diflSculty perceived, as the roots are 

 often of the same color. With the renewal of vine growth in the 

 Spring, this larva molts, rapidly increases in size, and soon commences 

 laying eggs. These eggs in due time give birth to young, which soon 

 become virginal, egg-laying mothers, like the first; and, like them, 

 always remain wingless. Five or six generations of these partheno- 

 genetic, egg-bearing, apterous mothers follow each other; when — 

 about the middle of July, in this latitude — some of the individuals 

 begin to acquire wingsf These are all females, and, like the wingless 

 mothers, they are parthenogenetic. Having issued from the ground, 

 while in the pupa state, they rise in the air and spread to new vine- 

 yards, where they deliver themselves of their issue in the form of 

 6gSP+ or egg-like bodies — usually two or three in number, and not 



•BalbiauL (Cjmptes Rendus Ac. d. Sc, Paris, September 21, 1874,) after a careful examination of 

 these individuals, says that they play no special physiological rule in the phenomena of reproduction ; 

 but that they have all the characters of the normal winged females, with, however, the generative 

 organs atrophied; and may, in part, be compared to the neuters among bees and ants. 



t During this virginal re^jroduction a gradual reduction in vitality and prolificacy is observable 

 from generation to generation. Around the flrst virginal mother the eggs may accumulate by the hun- 

 dred; but they decrease in number in succeeding generations until the individuals which— whether 

 winged or wingless — lay the sexual eggs, give birth in no instance, yet recorded, to more than eight. 

 From the true female again, or at the end of the cycle, only a solitary egg is born . 



J It has been a question whether the egg-like bodies from these winged females, or from the wing- 

 less mothers which produce them, can properly be called eggs, and M. Lichtenstein has proposed to call 

 them pupae, because they give birth, not to a larva but a perfect insect. The term "pupa" is, how- 

 ever, manifestly incorrect as applied to these bodies, because, when first laid, they are transparent 

 with a homogeneous content; while the sexual individual develops within the covering very much as 

 fhe embryonic lai-va develops within the egg. In f:ict we have here, not, as in Hippobosca, a larva 

 hatching and nourished in the $ abdomen until full grown and contracting to a pupa before delivered; 

 but an insect hutching and undergoing its entire development within the egg-covering after the egg is 

 delivered. Thus while the covering might more properly be called a sac just before the male or female 

 «re'eps out of it, it is more truly an egg when first delivered; and so it is best to call it. 



