APHID/E. 



523 



swellings on twigs like pine and spruce cones. The antemue 

 are short, five-jointed and slender; there are three straight 

 veinlets arising from the main subcostal vein and directed out- 

 wards, and there are no honey tubes ; otherwise these insects 

 closely resemble the Aphides. A species (Fig. 520; o, pupa 

 seen from beneath) closely related to the European Adelges 

 (Chermes) cocci neus of Ratzburg, and the A. strobilobiun of 

 Kaltenbach, which have similar habits, we have found in abun- 

 dance on the spruce in Maine, where it produces swellings at 

 the end of the twigs, 

 resembling in size 

 and form the cones 

 of the same tree. 



The most destruc- 

 tive insect of this 

 family is the Grape 

 Phylloxera, P. vlti- <> F 'S- >. 



J'oI/ J Fitch (P. v testatrix Planchon). It exists in two forms, 

 one raising irregular galls on the leaves, and the other form- 

 ing small swellings on the rootlets. The root-form is both 

 wingless and winged, the latter very rare. The leaf -form is 

 said to be always wingless. Fig. 521 (after Riley) represents 

 the wingless leaf- 



O 



form ; a, b, newly 

 hatched 1 a r v a, 

 ventral and dor- 

 sal view; c, egg; 

 <7, section of leaf- 



gall 



^j 



e, swelling 



of tendril ;/,</,/<, 

 mother gall-louse 

 lateral, dorsal, 

 and ventral 

 views ; , anten- 

 na;^', two-jointed 

 tarsus. Fig. 521 a, 



Fig. 521. 



</, healthy root ; 6, one on which the lice are working, repre- 

 senting the swellings caused by their punctures ; c, a root 

 which has been deserted by them, and where the rootlets have 



