PHYLLOXERA VASTATRIX. 61 



tliat the egg of the silkworm will bear a cold of 25° C. 

 in their passage over the mountains of Japan, and that 

 the caterpillars may be frozen, " so as to ring like metal 

 on a marble slab," and yet after a slow thawing they 

 will come to life and feed like others. The fond hopes 

 that cold would destroy the hybernating egg of 

 Phylloxera cannot therefore be realised. 



Balbiani states that the winged females deposit their 

 pseudova amidst the down on the underside of the 

 leaf ; and Riley says that this is the common habit of 

 the American species. The insect, however, will drop 

 them on the bark, or stem, or indeed almost any- 

 where. 



The produce of these last egg-like bodies, which 

 differ in size, is the true female from the larger, and 

 the male from the smaller variety. The sexes are both 

 mouthless, and live only for reproduction. The male 

 is comparatively active and visits many females, from 

 which it would appear that the last sex is in excess. 



The male and female. PL OXXII, figs. 7, 8. 



These perfect sexes I believe were first discovered 

 by M. Lichtenstein, and afterwards by Prof. Riley in 

 America. They are exceedingly small, and have no 

 true mouth parts. A small eminence is the sole 

 representative of the buccal organs. 



The apterous male. 



This minute insect is pale ferruginous yellow, 

 cycloid, flat, testudinate, with a very broad head 

 furnished with small black eyes. Thorax proper there 

 is none. The abdomen is coarsely ringed and corru- 

 gated. Legs short, with obtuse tarsi and very minute 

 claws. The male is so small that it may be easily 

 overlooked. 



The sexed female 



is much of the colour of the male but is larger. The 



