APHID^. 



523 



swellings on twigs like pine and sprnce cones. The antennse 

 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) coccineus of Ratzburg, and the A. strobilobius 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, J^. vttl- « Fig. 020. 



folicB Fitch (P. vastatrix Planchon). It exists in two forms, 

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

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

 wingless and winged, tlie latter very rai'e. The leaf -form is 

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

 the winj^less leaf- 



■r 

 d 



form ; a,h, newly 

 hatched larva, 

 ventral and dor- 

 sal view; c, ^^^\ 

 d, section of leaf- 

 gall ; e, swelling 

 of tendril; /*,r;', A, 

 mother gall-louse 

 lateral, dorsal, 

 and ventral 

 views ; i, anten- 

 na; J, two-jointed 

 tarsus. Fig. 521 r^, 

 «, healthy root ; h, one on which the lice are working, repre- 

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

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



