70 GALL-FLY. 



outline sketch of Insect Magicians by one or two of the most 

 plausible conjectures, as to the manner in which their natural 

 miracles are wrought through the prick of a needle, fit only 

 for the fingers of Queen Mab. 



The Ovipositor, or egg- inserting piercer, of the mother Gall- 

 fly, is, in some instances, conspicuously long; in others, only 

 partially visible, except on pressure, when it appears issuing 

 from a sheath, in form of a small curved needle longer than the 

 insect's body, wherein it is, however, rolled up by a curious in- 

 ternal apparatus. It is supposed, by Mr. Rennie,* that " after 

 the Gall-fly has made a puncture with this instrument, and 

 pushed her egg into the hole, she covers it over with some 

 adhesive gluten; or that the egg itself, as is usual among 

 moths, &c. may be thus coated over. In either of these cases 

 the gluten will prevent the sap that flows through the puncture 

 from being scattered over the leaf, and wasted ; and the sap, 

 being thus confined to the space occupied by the eggs, will 

 expand and force outwards the pellicle of gluten that confines it ; 

 till, becoming thickened by evaporation and exposure to air, it at 

 length shuts up the puncture, stops the further escape of the sap, 

 and the process is completed." The above explanation is, 

 however, only given as conjectural, and the one generally 

 adopted by French naturalists is, that the gall tubercle is 

 caused by irritation, in the same way as an inflamed tumor in 

 an animal body. 



* Insect Architecture, p, 371-3. 



