1898] A NEW METHOD OF ASEXUAL REPRODUCTION 31 V 



membrane of the embryos secondarily separated from these latter 

 and fused end to end. These deductions, although very plausible, 

 are not really in accordance with the facts. 



I have observed the oviposition of Encyrtus fuscicoUis. Now, 

 it does not lay its eggs in the month of May, but in the month of 

 July only a few days after being hatched ; moreover, its eggs are 

 not deposited in the caterpillar but actually in the egg of the 

 Hyponomeuta itself. The diminutive Chalcidian settles on a mass of 

 eggs fixed for some hours, successively stroking with its ovipositor 

 all or almost all the eggs in contact with it. I reserve the details 

 of this operation, which I have observed at length, for a forthcoming 

 memoir. I will only remark now, that tlie time occupied by the 

 Encyrtus in laying its egg in that of the Hyponomeuta varies from 

 half a minute to two minutes ; almost as soon afterwards there 

 follows another egg of the same laying, and so on for hours ; then, 

 when it has finished, it proceeds to another mass of eggs and begins 

 the same manipulations again. 



One important fact results from the foregoing observation. 

 Given a limited quantity of eggs in the ovaries of an Encyrtus, it is 

 practically impossible that, in the short time necessary for complet- 

 ing its oviposition, it should deposit in each moth's egg a number 

 of eggs equal to that of the embryos composing one of the chains to 

 which we have referred. A single egg must thus be laid in the egg 

 of the Hyponomeuta and this single egg must split up into a great 

 number of embryos. 



This inference has been proved by direct observation. I have 

 watched at the beginning of the evolution of the egg, and I have 

 ascertained that from the first its enveloping membrane is consti- 

 tuted like that of other known Chalcidians ; afterwards its cells 

 multiply rapidly, and it lengthens in a way to form the epithelial 

 tube. With regard to the cells which are found in the interior of 

 the enveloping membrane, instead of resolving into a single embryo, 

 as is the usual case, they dissociate in a way to give rise to 

 quite a legion of little morulac, which later become embryos and 

 arrange themselves in rows, as the envelope, increasing all the 

 time, passes from the primitive vesicular form to that of a long 

 flexuous tube. The whole product of the segmentation, however, is 

 not devoted to the formation of embryos ; from the beginning a 

 cellular mass in the form of a crescent is seen on the periphery ; 

 this gradually increases in size and dissociates pi'obably to form 

 the granular mass which fills the enveloping tube and unites the 

 embryos. 



From the preceding observation therefore, there results the dis- 

 covery, among the Arthropoda, of an entirely new method of repro- 

 duction to which I believe it is difficult to find anything analogous 



