Teras terminalis, 73 



For actual breeding purposes I allowed the flies to 

 pierce two little oaks ; on these they pricked six buds. 

 In the beginning of May two buds showed evidences 

 of gall formation : at the base of the bud a swelling 

 formed rapidly, and the real bud seemed to be 

 absolutely raised and set loosely on the gall, a proof 

 that gall formation springs from the meristem at its 

 base. At the end of May the galls were fully grown, 

 and proved to be those of Teras terminalis\ Whether 

 the experiments with Biorhiza aptera are made indoors 

 or out, it will always be found that in many of the buds 

 no gall formation occurs : the reason of this being that 

 the ovipositor of the fly causes an extensive destruction 

 of the tissues of the plant, and if no zone at the germinal 

 point remains intact, gall formation cannot take place. 

 The development of the bud is impossible w^here the 

 whole bud-axis is cut through. 



17^. Teras terminalis. Fbr.^ 



Gall. This gall grows, as the name indicates, chiefly 

 from terminal buds, but sometimes it may be found 



^ The connexion of the two generations Biorhiza aptera and Teras 

 terminalis has also been proved by Dr. M. W. Beyerinck, as I see 

 in a communication to the Entoniologische Nachrichten, vol. vi. 

 p. 45 (March, 1880). See Beyerinck, Bijdragc iol de Morphologie der 

 Plautegallen, Utrecht, 1877. 



[The root gall is found in September and October on Querciis pcdun- 

 cidata, Q. sessilijlora, and Q. pubescens. The gall lives about fourteen 

 months. 



Parasite. Torymns nobilis. It is stated by Curtis and others, that 

 Biorhiza aptera is polyphagus and occurs on beech roots. Cameron, 

 Hymenoptera, vol. iv, p. 13. 



2 Cynips qitercus-terminalis, Fbr.] 



