1882.] 225 



In November, at Montpellier, we find in abundance, under the 

 leaves of Quercus pubescens, the small flattened gall, in form of a small 

 shirt-button, applied to the lower surface of the leaves. These brown, 

 rather hard, galls fall to the ground in the winter, and from them, in 

 the spring, comes forth the Cynipid called Neuroterus lenticularis, 

 which is described by Reaumur. 



All the individuals of a species of this genus are identically the 

 same. They have been deemed to be females, because they have an 

 ovipositor and eggs, but, for my part, I believe they are without sex, 

 and their so-called eggs are gemmations. I consider them to be larval 

 forms, corresponding to the "phase emigrante," which I have described 

 in my " Considerations sur la generation des Pucerons ;" and I give 

 the reason why I so understand it. 



I found, in the month of April, a Neuroterus occupied in punc- 

 turing a terminal bud of a young oak. Over the little branch bearing 

 this bud, I slipped a tube like a lamp-glass which I fixed thereon, at 

 one end, by a cork cut in two pieces, and having a notch in the centre 

 to admit the branch, the other end with a cover of muslin. 



My Neuroterus was so busy with oviposition that it did not fly 

 away, and I was enabled to ascertain that it pierced the bud with its 

 long, spiral ovipositor, five times one after the other. The next day 

 it was dead, and fallen down in the tube, whence I removed it and 

 pinned it for my collection, having first assured myself by an attentive 

 examination that it was certainly Neuroterus lenticularis. 



I then substituted for the tube a covering of muslin round the 

 branch, sufficiently large to allow the leaves to develop, and in order 

 to avoid any error, I removed all the buds except the one that I had 

 seen pierced by the Cynipid. 



On the 20th April, five days afterwards, the leaves of this bud, 

 rather largely developed, bore five little galls of the size of small peas, 

 fleshy and transparent, like a white gooseberry, which were the well- 

 known galls from which Spathegaster baccarum is disclosed. 



Half of the miracle was thus beyond doubt : an insect of the 

 genus Neuroterus, proceeding from the hard, button-shaped galls of 

 the autumn, produces by its puncture the fleshy gall of the genus 

 Spathegaster. 



This last genus is sexuate ; it has males and females which copu- 

 late, and, if Dr. Adler has spoken the truth, which to me is beyond a 

 doubt, because I have seen it, the female of Spathegaster punctures 

 the leaves and deposits there the true egg, around which the Neuro- 

 terian gall is developed. 



