114 NATURAL SCIENCE. August. 1894. 



through an inherited instinct, each insect of a species forms a gall the 

 exact counterpart of the other. This would be marvellous enough, 

 but where the enclosed insect can apparently have no connection with 

 her cell for a considerable portion of the latter part of her existence, 

 it is even more astonishing, and the fact that the form of the galls 

 is influenced at an early stage is borne out by my observations that 

 many attacked by coleopterous and hymenopterous inquilines,^ which 

 have destroyed the coccid, still grow and increase in the uniform 

 typical shape distinctive of its species. 



The excessive flow of sap caused by the intrusion of the larva 

 into the tissue of the leaf or twig would naturally cause an after- 

 growth where the sap-circulation was altered, and naturally would 

 form an excrescence of aborted, diverted, woody fibre, but this cannot 

 account for a mass of galls with long curled horns or other decided 

 characteristics being evolved from such a simple cause. The final 

 shape of the gall must be directed by this tiny organism in some 

 wonderful manner as yet unknown to us. 



REFERENCES. 

 [The full descriptions and figures of the insects and galls referred to by Mr, 

 Froggatt in this article will be found in the following paper by him. — Ed.] 

 Notes on the family Brachyscelidae, with some account of their parasites, and 

 descriptions of new species. Part i. Proc. Linn. Soc. N.S.W., ser. 2, vol. vii., 

 PP- 353-372- pis. vi.. vii., 1893. 

 Part ii. Ibidem, vol. viii., pp. 209-214, pi. viii., 1894. 

 Part iii. Ibidem, vol. viii., pp. 335-348, pis. xvi., xvii., 1894. 



Walter W. Froggatt. 

 Technological Museum, Sydney, N.S.W. 



[1 Inquiline : an animal that lives in an abode properly belonging to another, 

 either at the expense of the latter, as in the present case, or merely as a co-tenant. — 

 Ed.] 



