188 PHILOSOPHICAL TRANSACTIONS. [anNO 1792. 



the natural act of copulation, by applying the male semen over the ova, just as 

 they were laid. The following experiments were made on the silk-moth. 



Exper. 1 . I took, a female moth, as soon as she escaped from her pod, and 

 kept her carefully by herself, on a clean card, till she began to lay; I then took 

 males that were ready for copulation, opened them, exposing their seminal ducts, 

 and after cutting into these, collected their semen with a hair pencil: with this 

 semen I covered the ova, as soon as they passed out of the vagina. The card 

 with these eggs having a written account of the experiment on it, I kept in a box 

 by itself. In the ensuing season, 8 of the ova hatched at the same time with 

 others naturally impregnated. Thus then I ascertained that the eggs could be 

 impregnated by art, after they were laid. The ova laid by females that had not 

 been impregnated, did not stick where they were laid: so that the semen would 

 appear not only to impregnate the ova, but also to be the means of attaching them. 

 To know whether that bag in the female silk-moth, which increased at the 

 time of copulation, was filled with the semen of the male, I made the following 

 experiment. 



Exper. 2. I took a female moth, as soon as she had escaped from the pod, 

 and kept her on a card till she began to lay. I then took females that were fully 

 impregnated before they began to lay, and dissected out that bag which I sup- 

 posed to be the receptacle for the male semen; and wetting a camel hair pencil 

 with this matter, covered the ova as soon as they passed out of the vagina. These 

 ova were laid carefully on the clean card, and kept till the ensuing season, when 

 they all hatched at the same time with those naturally impregnated. This proves 

 that this bag is the receptacle for the semen, and gradually decreases as the eggs 

 are laid. 



Of the sting of the bee. — I have observed that it is only the queen and the 

 labourers that have stings; and this provision of a sting is perhaps as curious a 

 circumstance as any attending the bee, and probably is one of the characters of 

 the bee tribe. The apparatus itself is of a very curious construction, fitted for 

 inflicting a wound, and at the same time conveying a poison into that wound. 

 The apparatus consists of 2 piercers, conducted in a groove, or director, which 

 appears to be itself the sting. This groove is somewhat thick at its base, but 

 terminates in a point; it is articulated to the last scale of the upper side of the 

 abdomen by 13 thin scales, 6 on each side, and 1 behind the rectum. These 

 scales inclose, as it were, the rectum or anus all round; they can hardly be said 

 to be articulated to each other, only attached by thin membranes, which allow 

 of a variety of motions; 3 of them however are attached more closely to a round 

 and curved process, which comes from the basis of the groove in which the sting 

 lies, as also to the curved arms of the sting, which spread out externally. The 

 '2 stings may be said to begin by those 2 curved processes at their union with the 



