86 THE ENTOMOLOGIST. 



should not have sprung. The leaf and petiole in the normal 

 state are capable of throwing out shoots, and in this case 

 there is no apparent change in the general parts of the 

 structure, and if from abnormal stimulus a shoot was tlirown 

 out oviposition would give us an abnormal gall, coinciding 

 in many points with the one under consideration of Cynips 

 Kollari. However, though this is apparently possible, we 

 have not sufficient knowledge of the structural alterations to 

 admit its probability, and as the very essence of the charac- 

 teristic of the Kollari gall is to lose all trace of its origin in 

 its progress of growth, even should the case have been so, it 

 must rest unproved. 



The matter, however, is very interesting as a clue to 

 variations of structure, and some experiments on the results 

 of stimulating or condensing the flow of sap in the early 

 stages of the growth of Kollari galls, by ringing, or heading 

 back the shoots, might give us some valuable physiological 

 information. 



Judging from experiments with others o\ the Cyuipidts, 

 abnormal oviposition might readily be effected. Aphilothrix 

 radicis will oviposit in oak buds in captivity ; and on the 

 13th of December, in the last year, I was fortunate enough 

 to capture two specimens of Biorhiza aplera in the very act 

 of ovipositing in the buds of the branches of an old oak at 

 about seven feet from the ground. Being anxious to secure 

 the insects for identification beyond my own examination, 1 

 was obliged to draw down the boughs and break off the 

 sprays, but even this did not disturb ihem, so that in one 

 case I was able to watch the operation for some minutes, and 

 in the other (as I slightly injured the creature in gathering 

 the spray) the ovipositor was just pressed from the bud, 

 with an egg in the act of protrusion. One of the specimens 

 subsequently (as far as could be seen through a fine net) 

 proceeded with oviposition on two buds of an oak in my own 

 garden ; and as I have noted the then state of the spray, 

 and isolated it, some curious results may be hoped for. 



On examining the buds, amongst whicli 1 first found the 

 Biorhiza ovipositing, 1 found one to contain a mass of eggs, 

 similar in their peculiar shape (which is elongated at one end, 

 to a somewhat flask or stalked form), to others which 1 have 

 taken from the abdomen of Cynipidau on previous occasions. 

 These I have placed, with the bud-scales (which shield them 

 still, though broken from the bud-base), in a small slit made 

 in the bark below the ground level of the same oak in my 



