APHILOTHRIX CALLIDOMA. / / 



Aphilothrix callidoma, Haitig. 

 (Plate XVIII.) 



Cynips callidoma, Thomson ; Andricus callidoma, Mayr, Cameron ; 

 Apliiloihrix callidoma, Liclit., Mayr, Fitch, Adler, Mosley. 



English name of gall. — " The Stalked Spindle Gall." 



Position of gall. — ^Axillary buds. 



Manner of growth. — Solitary, glabrous, glossy, spindle shape. 



Colours. — Pale green, green, yellowish-green, lirown. 



Average dimensions of a mature specimen.— Length, 

 18 mm. ; girth, in centre, 9 mm. 



May be sought during the months of May to October. 



Growth is complete by the end of August. 



The typical condition of the gall is unilocular and unilarval. 



The larva pupates in the gall. The imago emerges during the 

 following spring. 



Parasite, No. 111. Inquilines, Nos. 133, 145. 



Alternate sexual generation : Andricus cirratus, Adler. 



The elegant shape and marked originality in the 

 form of this gall distinguishes it above all other 

 British oak galls. 



It grows from an axillary bud, but more frequently 

 on the slenderest twigs of stub-oaks, and near the 

 ground, than in any other situation. Once only have 

 I found a specimen on a branch as high up as ten 

 feet from the ground. It is shown as an inset in 

 Plate XVIII. 



The o-all is cylindrical in outline, with each end 

 attenuated, producing a fusiform or spindle-shaped 

 growth. Each attenuation is solid, usually of great 

 length, the basal one generally the longest, sometimes 

 twice or three times longer than the central portion ; 

 the distal end may be short and recurved. 



The larval chamber is situated in the centre. During 

 growth it is difficult to decide without dissection where 

 the gall is solid — the enlargement is so gradual. AVhen 

 dry the attenuations shrink (in thickness only) almost 

 to a thread. As the larval chamber does not shrink 

 it can then be easily located. Its cell walls are very 



