66 BRITISH APHIDES. 



chrysalis of two different sizes, giving birth to males 

 and females. These last are laid by the Pseudogynce 

 of the fourth stage. 



I must acknowledge that the word pupifer is not 

 perfect ; as in many species the males and females are 

 born alive, because the fine skin by which they are 

 surrounded bursts at the moment of laying. 



However, I gave all names after a full consideration 

 of the biology of Phylloxera querc&s ; and as in this 

 species the sexuated insects remained some days in 

 their egg-shaped pupa3, I inadvertently selected a 

 name which is not equally well adapted to all Aphides. 



Of the sexuated forms, male and female, I have 

 little to say. The females seem always to be apterous, 

 the males occur both with or without wings in the 

 same genus, and even in the same species. 



I now hasten to describe my classification of the 

 genus Phylloxera — or I would rather say of the family 

 Phylloxeridse, for I think it is not possible to retain 

 under the same genus the numerous species already 

 known. 



Phylloxerire. 



These are easy to distinguish from all Aphides by 

 their three-jointed antennas, shown in all their life- 

 stages. This is a good plastic character, and 

 separates the Phylloxerians from all other insects of 

 their class. It is a fact that each of the four life- 

 stages of the above-mentioned family is separated from 

 the following one by an egg-like quiescent state; so 

 that the Pseudogyna 1 , which seem to be viviparous in 

 other Aphides, here appear to be oviparous. With 

 the Phylloxerians these may be looked upon as 

 pseudova.* 



* I have had no opportunity to study the Chcrinesians, which are, 

 ]n ili.i).-. also oviparous ; but the genua Vacuna, which is mentioned by 

 Borne authors as oviparous, I can testify is certainly viviparous. 



N.B. — J\Iy own observations on Thelcutee dryophua | Vacu/nai) also pul 

 la. i beyond doubi However, Vaouua has boon confused with 

 Phylloxera by Borne authors. — G.B. B. 



