70 Miscellaneous. 



it, the fish descends in the water ; it rises again by relaxing the 

 muscles which had served to compress the bladder. Moreover, the 

 fish may remain at the bottom of the water, by the very fact of the 

 pressure of the column of water on the air contained in the bladder. 

 By compressing more or less the posterior portion or the anterior 

 portion of the bladder, the animal is able to render the anterior half 

 or the posterior half of its body lighter at will ; it can also take an 

 oblique position, which allows a movement of rising or of descending 

 in the water. The arrangement of the natatory bladder in some 

 fishes might favour this action. The Cyprinoids and the Characi 

 have two bladders, one before the other, and communicating together 

 by a narrow tube. The anterior bladder is very elastic, whereas the 

 posterior one is very slightly so ; and in proportion as the fish rises 

 in the water, the anterior bladder, which is the most elastic, must 

 considerably increase in volume, and thus keep the head of the 

 animal up, whilst the contrary must be the case when the fish de- 

 scends. — Mullers Archiv, 1845, p. 456. 



CICONIA ALBA. 



A fine specimen of the Stork (Ciconia alba, Ray) was shot a few 

 weeks since near Fermoy in the county of Cork. It appears that three 

 individuals were seen, but this only was procured. It is now in the 

 possession of the Rev. Mr. Bradshaw of this city. I am not aware of 

 any authentic record of the species having been met with in Ireland 

 before. J. R. Harvey, M.D. 



Cork, June 17, 1846. 



Embryogeny of the Ornithomyice. By M. Blanchard. 



The Ornithomyice, or Pupipares of Latreille, are parasitic on mam- 

 miferse and birds. They have for a long time attracted the attention 

 of entomologists, by an exceptional mode of reproduction which 

 distinguishes them from all other insects. They do not deposit eggs, 

 nor even larvae, like some other Diptera, but nymphs, the external 

 envelope of which hardens in contact with the air, and from which 

 issues a few days afterwards the perfect insect. 



Anatomists are not agreed as to whether the embryos pass, in the 

 maternal ovary, through the ordinary phases of the metamorphoses 

 of insects. Latreille supposed that the nymphs are at first under the 

 form of eggs, and pass their life as larvae within the body of the 

 mother. Leon Dufour, from examinations of the Hippoboscus of the 

 horse, and the Melophagus of sheep, thinks, on the contrary, that 

 the embryos of the Omit homy i* are never comparable to eggs or to 

 larvae. 



M. Blanchard has examined the Leptotena of the stag, and he iias 

 found, in the ovary of the females, embryos which completely re- 

 semble the larvae of the Diptera, by their soft teguments, their cor- 

 neous head, their two long tracheae, and their nervous system collected 

 in the anterior part of the body. The only important difference 



