ALTERATION OF FORM BY GALL-PRODUCING INSECTS. 



541 



several Cynipedes, e.g. Aphilotrix Sieboldi (see fig. 364 ^) lay their eggs in the green 

 cortex of the young twigs. Solid galls are very rare on roots, but they do occur 



Fig. 364.— Various Oak-galls. 



1 Solid galls on the cortex produced by Aphiloihrix Sieboldi. - Bud-gall from a foliage-bud produced by Cynips Hartigii. 

 ä Solid galls on an Oak twig produced by Cynips Eollari. * One of these galls cut in half. ' Bud-galls from foliage-buds 

 produced by Cynips lucida. « One of these galls cut in half. " Leafy bud-galls produced by Aphilothrix gemmce. 

 8 Bud-galls from foliage-buds produced ))y Cynips polycera. a Longitudinal section through one of these galls, w Gall 

 on the pericarp of Quercus pubescens produced by Cynips caput-medusce. n-n Spangle galls on a leaf of the Turkey Oak 

 {Quercus Cerris); n produced hy Neuroterus lanuginosus ; 12 by Neuroterus nwnismatis ; is by Neuroterus fumipennis; 

 14 by Spathegaster tricolor. 



in this situation in the oak, being produced by the gall- wasps Aphilothrix radicis 

 and Biorhiza aptera. 



