AI'H1L(3THKIX CORTICIS. 81 



The larva pupates in the ^-all. The imago emerges during 

 June. 



Parasite, No. 158. InquiUne, No. 131. 



Alternate sexual generation : Andricus (jeiiiniafm, Acller. 



This species of gall is often more or less concealed 

 by dead leaves, moss, oi' loose earth, l)iit sometimes 

 sitnated prominently in a callus or other incrassation 

 of a sttib. 



The autumn-winter condition of these galls is shown 

 in Plate XXII, div. A. 



Embedded deeply in the bark, and not easy to see, 

 because of their brownish colour, these galls are 

 constantly overlooked. It is only during the very 

 earliest period of exposure, and later on after the 

 imagines have eaten their way out, that the galls 

 attract attention — in the former condition by reason 

 of their pale colour, in the latter, T)ecause of the 

 clusters of little holes. 



They occur in aggregations, and vary in numbers 

 from three or four to forty or more, very rarely less 

 than three ; mostly in a deep split in the bark ; 

 frequently in a callus resulting from injury, or in the 

 new growth wdiere a limb has been removed ; some- 

 times in semi-exposed roots ; and occasionally in the 

 axis of a bough growing out from the Ijole of the tree. 



The shape of this gall is fairly constant, obconical 

 being the type. It varies, how^ever, especially during 

 the period before maturity, Avlien it may be oval with 

 the lower apex somcAvhat pointed ; this ultimately 

 penetrates deeply into the tissue around it. AVhen 

 conglomerated they are often greatly distorted, 

 flattened longitudiually, and irregular in size and 

 form. 



The appearance of the gall when pushing through 

 the bark is glossy, succulent, and fleshy, very pale 

 yellow, or greenish. The visible portion known as 

 the cap is more or less globose, and about 8 mm. in 

 diameter. The structure continues to rise until it is 



C) 



