68 BEITISH APHIDES. 



Phylloxera coccinea, Heyden. 



— corticalis, Kaltenbach. 



— punctata, Lichtenstein. 



— acantho-chermes, Kollar (sub. Acantho- 



chermes quercus). 



The yellow, black-spined Phylloxera corticalis feeds 

 only on the trunk and twigs of Quercus pubescens, and 

 was found by Kaltenbach at Aix in 1862. Its habitat 

 does not allow one to confound it with any other species. 

 I believe its economy is similar to that of Phylloxera 

 (j uc re us, but without its migration. I know the 

 Pseudogyna migrans, gemmans, and yupifera. I have 

 not yet obtained the sexuated forms.* 



Phylloxera coccinea, P. punctata, and P. acantho- 

 chermes all feed under the leaves of Quercus robur. 

 P. coccinea forms a gall-like folding of the leaf-edges, 

 under which it lays the pseudova from which the 

 emigrants issue. 



I am not sure if these become winged ; for about 

 the time in which that metamorphosis ought to take 

 place, clouds of emigrants of Phylloxera quercus arrive 

 on the same trees, and I have not been able satis- 

 factorily to isolate one species from the other. The 

 foundresses {Pseudogyiuv fundat rices) of each species are 

 very different. In Ph. quercus she is active, large, 

 and tuberculated ; whilst in Ph. coccinea she is quite 

 smooth, and lies in a gall. This last insect is found 

 also at Paris, and was discovered at Frankfort by 

 von Heyden. I received winged pupifera) from M. 

 Signorot, which furnished me here with pupce, from 

 which I obtained males and females. 



I consider Phylloxera punctata to be an inhabitant 

 of the mountains, having seen it only in Switzerland 

 and in the Pyrenees. Here we meet with the unusual 

 circumstanco that, while in all the preceding species 

 tho pupiferous form is winged, it is apterous in Phyl- 

 loxera punctata. Thus the pupa3 of two different 



* Since tliis was written I obtained in my breedings the very small 

 Kcxuat< (1 forma of that species on the first of October. 



