ALTERATION OF FORM BY GALL-PRODUCING INSECTS. 



541 



several Cyuipedes, e.g. Apkilotrix 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. 



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

 8 Solid galls on an Oak twig produced by Cynips Eollari. 4 One of these galls cut in half. 5 Bud-galls from foliage-buds 

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

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

 on the pericarp of Querais pubesceiis produced by Cynips cap^tt-medusce. n-i* Spangle galls on a leaf of the Turkey Oak 

 {Quercus Cerris); i' produced by ^'eiirotcrus lamigiiwsus; 13 by ^euroteriLS numismatis ; 13 by Neuroteriis fumipennis; 

 n by Spathegaster tricolor. 



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

 and Biorhiza aptera. 



