ALTERATION OF FORM BY GALL-PBODUCING INSECTS. 



541 



several Cyuipedes, 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. 



I Solid galls on the cortex produced by Aphilothrix Sieholdi. 2 Bud-gall from a foliage-bud produced by Cynips Hartigii. 

 8 Solid galls on an Oak twig produced by Cynips Kollari. i One of these galls cut in half, s Bud-galls from foliage-buds 

 produced by Cynips lucida. s One of these galls cut in half, 7 Leafy bud-galls produced by Aphilothrix gemmce. 

 8 Bud-galls from foliage-buds produced by Cynips polycera. 9 Longitudinal section through one of these galls. 10 Gall 

 on the pericarp of Querous pubescens produced by Cynips caput-medusoB. n-i* Spangle galls on a leaf of the Turkey Oak 

 {Qiterms Cerris) ; u produced by Neuroterus lanuginosus ; 12 hy Neuroterus numismatis ; i^ by Neuroterus /uniipennis ; 

 " by Spathegaster tricolor. 



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

 and Biorhiza aptera. 



