38 MUTISH APHIDES. 



itself. As before noted, however, Koch thought this 

 a character sufficiently marked to justify his genus Ani- 

 sophleba. The under wings have but one oblique vein. 



A gentle pressure on the abdomen causes the insect 

 to exsert the prehensile hooks, which I believe Ratze- 

 burg mistook for a penis, and thus he looked on 

 certain slightly different alate insects as the males of 

 Chcrmes la/ricis. 



These winged females, after finding a suitable spot 

 for oviposition, exclude their eggs in considerable 

 numbers, clothe them with the down from their bodies, 

 and then die. Their dry skins, with the wings at- 

 tached, form, as in the last species, a certain protec- 

 tion over the eg^gs. Throughout all the summer 

 apterous and winged females may be seen ovipositing 

 side by side until the succulency of the sap is too 

 much reduced to give nourishment. 



The males and true females of CJtennes Jar ids are 

 yet to be discovered, and inquiry is yet desirable as 

 to the fact whether the last be apterous or winged ; but 

 I believe that the true egg is laid by an apterous 

 insect and hatched in autumn. Without such a habit 

 we cannot explaiu the hybernation of the queen mother. 



I hesitate to adopt Koch's observation that the 

 smaller winged insects which appear simultaneously 

 with the apterous are real males and females. The 

 former, under his view, might have been males ; but it 

 has not yet been demonstrated that any real females 

 among the Aphidina3 are otherwise than apterous.* 



The hybernation of Chermes is a fact. I have dis- 

 covered the insect secreted in the bark-fissures, near 

 the incipient leaf-buds, as late as December 12th and as 

 early as February 27th. At the former date I could 

 find no evidence of enclosed eggs, or rather they were 

 limited to mere rudiments. 



The alimentary canal was easily traced, and there 

 were several blind sacs visible within the posterior rings, 

 which in all probability were the colleterial glands. 



* Koch, ' Die Pllauzculiiuse,' p. 317. 



