FOKMS OF GALLS. 15 



Nor must the hard and woody nature of these large 

 galls be omitted from mention as a means of defence, 

 for obviously they can be attacked by insects only 

 during the short period they are soft. 



Conversely, the small size of the gall is a protec- 

 tion — first, by hiding it, making it less easily seen by 

 parasites ; and secondly, by its small size offering 

 sustenance to only one inquiline — e. g. Andricus nudus, 

 albipes, pilosus. 



Second, Colour. — Colour as a protection is best 

 seen in the small catkin galls. At first green, like the 

 young catkins, they with age become brownish, like 

 the old catkins ; and this resemblance is, in some of 

 them, further increased by their being pilose, e. g. 

 Andricus amenti. 



Third, Smell. — This phenomenon is doubtless 

 accompanied by some noxious principles which make 

 the larvas unpalatable to birds, &c. ; and is, as men- 

 tioned above, 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. Gynips 

 Kollari and Bryophanta foli are cases in point. The 

 smell given out is usually bug-like, but Paszlavszky 

 (Wien. Ent. Zeit., 1883, 130) mentions that foli 

 has the smell of ripe apples ; A. radicis of lemon; A. 

 Sieboldi and Gynips tinctoria of caramel, or fresh malt, 

 with a trace of bug- smell. According to the same 

 authority, the foli individuals bred from the sessile oak 

 have the smell much more intense than those from the 

 pedunculated. 



Of the Bedeguar gall-flies, Reaumur says (Memoir, 

 iii, p. 494) that they have a quality which he had not 

 met with in other gall-flies, namely, that they have a 

 smell which is attractive to cats. 



Fourth, Clothing and Texture. — The long hairs sur- 

 rounding the galls of many species, often (especially 

 when young) more or less glutinous, afford protection 

 to the larvse. In other species the surface exudes a 

 glutinous secretion. 



