18 BRITISH OAK GALLS. 



tlie oak-apple. It is on record (' Alternating Grenera- 

 tions,' pp. 77-79) that Mr. Francis AYalker reared 

 from a number of these galls specimens of Insects, 

 Arachnid£e,and Acari, belonging to seventy-five species. 

 The effect upon this gall is to increase its rotundity 

 rather than to produce malformation in its contour. 

 A normal mature specimen measures about 8 cm. in 

 girth, whereas one containing a host of inquilines and 

 parasites measured 18 cm. in girth — an exceedingly 

 fine specimen. 



Smell. 



Collectors of galls are aware that many species 

 possess a distinctive odour, which it would appear acts 

 as a means of defence ao-ainst enemies other than 

 inquilines and parasites. 



Cameron has ably summed up the siil)]'ect in the 

 following manner : " This phenomenon is doubtless 

 accompanied by some noxious principles which make 

 the larvae unpalataljle to birds, etc., and is found 

 chiefly in the larger species which inhabit large galls 

 all the year round. Both the larva and imago may 

 give out an offensive odour. C. Kollari and Dri/npltanfa 

 foJii (= Rc at pilaris of this work) are cases in point. 

 The smell given out is usually bug-like, but 

 Paszlavsky (''AYien. Ent. Zeit.,' 1888, 130) mentions 

 that D. folii has the smell of ripe apples, A. radicis 

 of lemon, A. Sieholdi and G. tincforia of caramel or 

 fresh malt, with a trace of bug-smell. According to 

 the same authority the folii individuals bred from 

 the Sessile-Oak have the smell much more intense 

 than those from the pedunculated species " (' Brit. 

 Phyto. Hymen.,' vol. iv, p. 15). 



Taste. 



The taste of oak galls to the human palate does not 

 appear to have been described in any writings. That, 



