THE BUTTERFLY AND ITS ALLIES 



39 



egg, or by the irritation of the developing embryo. 1 The 

 galls of gall-wasps are often more or less spherical masses 



FIG. 38. Ophion, an Ichneumon which infests caterpillars. Nat. size. Photo, 

 by W. H. C. P. 



which are closed, in consequence of which the confined 

 insect must bore its way out. The galls made by the same 



FIG. 39. Larvae of saw-fly on grape leaf. Photo, by V. H. L. 

 1 Cf. Fig. 69, p. 67. 



