1 66 Appendix I. 



he secured around suitable oak twigs. He never actually 

 succeeded in seeing the egg laid, as the flies are shy in 

 confinement ; and in hundreds of buds which he examined 

 he only found the ^g^ in four, and some of these were found 

 the first day the flies were in the nets. The ^^^ is 2*5 mm. 

 long, and can therefore be easily recognized. 



On May 28, 1882, the first sign of gall formation was visible. 

 On June 9, the larva was completely walled in, and the larva 

 chamber closed on all sides. In July the tissues above the 

 scar died and dropped off, leaving the bifid apex uncovered, 

 and disclosing a gall 10 mm. in diameter of a grass green 

 colour. In September growth was complete, and in October 

 the gall-fly emerged. 



C Kollari as a rule seeks out a weakly shoot in October, 

 and pierces the petiole of the lowest rudimentary leaflet 

 of a bud, depositing its ^g^ laterally, on the front of the 

 petiole, and between it and the little secondary bud about 

 to form in the axil of this leaflet. A blastem grows up 

 around the egg-body, gradually closing over it, and pressing 

 the larva out of the egg-shell, which is held back by the stalk. 

 As the petiole of the leaf grows, the canal, with the egg-stalk 

 in it, is carried upwards, and the egg-shell is thus torn out 

 of the blastem. 



The gall of C. Kollari is widely distributed in Italy, France, 

 Austria, Holland, and in Germany as far north as the Elbe. 

 In England it appears to have been introduced at Exmouth 

 about fifty years ago at a time when cloth manufacture was 

 extensively carried on in Exeter, Tiverton, and other towns 

 in the west of England ; but whether the gall was first 

 imported for dyeing purposes is not known. Canon Derham 

 does not mention having found it, although he was well 

 acquainted vdth the Aleppo gall. It spread slowly over the 

 county, and from this circumstance it came to be called the 

 Devonshire gall. 



Cynips Kollari created quite as much sensation in its time 

 as the Colorado beetle or the Hessian fly. As late as 1852 

 it w^as averred that the gall was utterly destroying the crop 

 of acorns, used for feeding pigs, and that the loss to farmers 



