122 



THE AMERICAN BEE JOURNAL. 



Musea vomitoria. In Musca vomitoria and its 

 allies, which had not yet completed the business 

 of ovipositiou, or perhaps had been disturbed in 

 it and had not immediately met Avith another 

 suitable place for the deposition of their eggs, the 

 eggs occuring in the ovarian tubes and in the 

 oviduct differed in the following extremely in- 

 teresting manner. Tlie egg which was fixed 

 between the vulva and the orifice of the seminal 

 receptacle, had already begun to develope itself 

 and contained an embryo, whilst the egg found 

 in the oviduct above the orifice of the" seminal 

 duct, Avhich was perfectly equal in size with the 

 preceding one, did not betray a trace of the com- 

 mencement of the development of the embryo, 

 any more than the eggs contained in the Fal- 

 lopian tubes. In such female flies the seminal 

 receptacle always contained mobile spermatozoa. 

 At that time we contented ourselves in the ex- 

 planation of the process of fecundation, with the 

 supposition that the contact of the spermatozoids 

 sutficed to incite the egg to development. More 

 recently we have been compelled to drop this 

 theory of contact, since we have been able to 

 trace the penetration of the spermatozoids into 

 the interior of the (^gg. The process of impreg- 

 nation will now have to be more precisely con- 

 ceived in the following manner: The fecundation 

 and capability of the development of the egg are 

 not produced merely by the immediate contact 

 of the semen with the e.gg^ but the elementary 

 constituents of the semen, the mobile seminal 

 filaments must actually slip into the interior of 

 the egg^ very probably to become destroyed here 

 first, to be dissolved and then mixed with the 

 elementary constituents of the egg.* For this 

 purpose the eggs of insects possess a micropylar 

 apparatus, that is to say, one or more small aper- 

 tures at one of the poles, through which the 

 spermatozoids must get into the interior as far as 

 the yelk of the egg, in order to complete the act 

 of fecundation. 



Leuckart was the first to set himself the task 

 of ascertaining by direct observation, to what 

 modifications tJie penetration of the spermato- 

 zoids through the micropylar apparatus of the 

 eggs of the bee would be subjected according to 

 Dzierzon's theory. For this purpose he went to 

 Seebach at the end of May last year, in order to 

 be able to make use of the most abundant selec- 

 tion of the necessary objects for investigation. 

 A better opportunity for such investigations could 

 be presented to him nowhere else than in the 

 immediate vicinity of the grand bee-establish-, 

 ment at Seebach, in which, however, we must 

 also take into account the disinterested liberality 

 with which Herr von Berlepsch sacrificed his 

 apiarian riches for the purposes of such physio- 

 logical and anatomical investigations. 



Leuckart' s intention had already been an- 

 nounced by Berlepsch in the Bienenzcitiing^ and 

 I was therefore extremely anxious to know what 

 results Leuckart would obtain from these See- 

 bach studies. These have been recently pub- 

 lished by Leuckart in the above-mentioned jour- 

 nal, from which I will here communicate the 

 most important of the results. 



*The cases of true parthenogenesis are, of course, to be 

 understood as forming the exceptions to this rule. 



Leuckart was, of course, obliged in the first 

 place to turn his particular attention to the mi- 

 cropylar apparatus of the eggs of bees, of which 

 he gave the folloAving description; "As in the 

 eggs of most insects we distinguish in those of 

 bees two membranes, an inner one the so-called 

 vitelline membrane, and an outer one the egg- 

 shell or the chorion. Both membranes are ex- 

 tremely thin and delicate: even the outer one, 

 which otherwise (especially in those eggs which 

 are deposited freely) is of considerable thickness 

 and firmness. The vitelline membrane is struc- 

 tureless, whilst the chorion is covered with a 

 delicate hexagonal lattice work, as with a net- 

 work, as far as the hinder (lower) flattened end 

 of the Qgg which "feerves for its attachment. The 

 micropylar apparatus lies at the anterior or su- 

 perior pole of the egg, .which is last excluded 

 during oviposition (and afterwards contains the 

 head of the young larva. At this point where 

 the ridges of the chorionic network run together, 

 we see a little fi^n-shaped figure (of about 1-70 

 millim. ) with about twelve rays. The rays of 

 whicli the lace is composed form the optical ex- 

 pression for the same number of micropylar 

 canals which run under the surface of the cho- 

 rion. At their lower diverging ends these canals 

 are open externally, whilst they open into the in- 

 ternal space of the eggs with their opposite ex- 

 tremities. The structure is exactly the same as 

 in a number of other hymenoptera, but with this 

 distinction, that in this case the micropylar 

 canals are most extraordinarily thin and deli- 

 cate, so that we can hardly convince ourselves 

 with certainty of their real nature, and at the 

 first glance might be inclined to regard the rays 

 as ridges, such as also occur on other parts of 

 the chorion. The canals can hardly be more 

 than one five-thousandth part of a millimetre in 

 diameter, though certainly still sufficient to al- 

 low the passage of a seminal filament. During 

 the last period of its stay in the ovary, the bee's 

 egg receives another external coating of an al- 

 buminous nature, which, indeed, is reduced to 

 almost nothing on the anterior (superior) half, 

 but gradually thickens posteriorly, and acquires 

 a very considerable development at the flattened 

 posterior (inferior) pole. This albuminous de- 

 posite serves for the attachment of the egg to the 

 wall of the cell." Although I do not quite agree 

 with the Leuckartian conception of the micropy- 

 lar apparatus of the bee s eggs, and am especially 

 compelled to regard the above-mentioned mi- 

 cropylar canals as something else, a detailed 

 criticism of this representation of Leuckart' s 

 would lead me too far, and I therefore reserve 

 this for another occasion, and will make use of 

 the expression micropylar apparatus, without 

 connecting therewith exactly the same idea as 

 that which has been formed of it by Leuckart. 

 The possibility of success in the before-mentioned 

 artificial impregnation must depend as Leuckart 

 has very justly observed, upon the thin albumi- 

 nous coating of the eggs of bees; for as soon as 

 this albuminous coat has dried, which will cer- 

 tainly be the case within a few minutes of the 

 deposition of the eggs in the waxen cells, the 

 orifices of the micropylar apparatus will be plas- 

 tered over with it, so that the seminal filamfints 



