CYCLOPIDjE. 191 



antennse, he immediately conjectured that the organs re- 

 sided in the swelhngs which mark the antennas of the 

 male, and were applied to the vulva, which he correctly 

 enough states to be situate in the abdomen.* This mis- 

 take, however, Jurine has cleared up, having demonstrated 

 the organs in both sexes, and watched the act of copula- 

 tion itself. When the mother is about to lay, we may 

 perceive the material of the eggs, which I have described 

 above under the name of internal ovary, divide into two 

 columns, one on each side, and pass through the canalis 

 deferens, covered with a fine pellicle, which forms the sac 

 in which the eggs are contained when extruded. This 

 bag of eggs, or external ovary, remains suspended at the 

 tail of the female for several days, varying from two to 

 ten, according to temperature of weather, &c.t The eggs 

 themselves, during their sojourn there, do not increase in 

 size, but undergo various changes in colour, &c., and at 

 the proper time the ovary opens, and the young ones are 

 ushered forth into life, as unlike the parent as can well be 

 imagined. I have already said that Leeuwenhoek has 

 noticed this difference between the young and old, and 

 upon first observing it, he appears to have been much 

 surprised at the unexpected discovery. He repeated his 

 experiment, therefore, of separating an insect, with the 

 ova attached to the tail, and found the same result : "Ex 

 hisce visis," he concludes, "certa milii persuasi ea ani- 

 malcula, quae jam oculis meis observabantur, ex ovis illis 

 nata esse."j He watched them for seven or eight days, 

 and found them increased in size ; but here, when just on 

 the threshold of discovery, he seems to have stopped, and 

 he makes no further mention of a continuation of his 

 observations. 



De Geer also noticed this curious fact, confirms the 

 observations of Leeuwenhoek as far as they went, gives 



* Entomost., pp. 16, 1 7. 



t Leeuwenhoek says they extrude their ova in the space of one day or 

 night, and bring them to perfection in the space of three days. — Epist. ad 

 Soc. Reg. Ang. 



t Epist. ad Soo. lleg., p. 139. 



