74 BRITISH APHIDES. 



kind in those species of Aphides which, like Pemphigus, 

 Tetraneura, and Phylloxera, get their nourishment 

 from ligneous trees and plants ; for on the same 

 vegetables they not only feed but secure safe harbour 

 for their eggs during the winter. It is chiefly with 

 reference to those Aphides which live on annual plants ; 

 the stems of which die down every year, that it would 

 be interesting to know what becomes of them during 

 the many months in which no food appears to be 

 provided for them. 



Dr. G. Balbiani informs me in his letter, dated 

 January of this year, that " In the Bois de Meudon, near 

 Paris, Siphonophora millefolii was exceedingly common 

 in 1866. Colonies were very abundant upon almost 

 all the tufts of Achillia millefolium, which plants were 

 almost covered by them. In autumn the males and 

 females appeared, and I many times witnessed the 

 coupling of the red-winged males with the apterous 

 females, which last were green like the agamic 

 individuals. During nearly a whole month during 

 which I observed them, I never saw one egg fixed to 

 :i leaf or to a stem of Achillia." 



" I then examined the turf below, and to my surprise 

 I found a large quantity of eggs which were nearly 

 black and sticking to the leaves of several grasses and 

 plants as Gyperacea t Trifolium prateme, &c. 



" I took home with me several handfuls of these 

 sedge plants and grasses, and at the end of February, 

 L867, they were covered with a number of active little 

 ' puccrons ' of Siphonophora millefolii." 



We may conclude, therefore, from this observation ; 

 which has a bearing on the history of other Aphides 

 living on anniml plants, that when the females have 

 coupled fchey quit the branches and lay their eggs in 

 the soil on grass or on any vegetable <lr/>n'i< which will 

 remain throughout the winter. Thus these progenitors 

 shelter their eggs even more securely than the progeni- 

 tors of those which oviposit on plants. M. Balbiani 

 further tells me that he has also made observations on 



