44 EXTRACTS FROM FOREIGN PERIODICALS. 



hinder part higher than in front ; the legs longer and the body thinner than in the 

 common Fox. The hair is of a tawny colour on the upper parts, grey under- 

 neath; the throat, lips, and tip of the tail, are pure white. — This animal exhales 

 no fetid odour. It lives in considerable herds, amounting sometimes to fifty 

 individuals, which hunt in company, attacking Gazelles, Sheep, and Calves. So, 

 at least, observes M. Bodichon, the Arabs tell me ; I have never myself seen 

 more than six or seven together. It is not found in mountainous countries, so 

 that the French possessions known by the name of Massif dAlgar are deprived 

 of it. It sometimes occurs in the plain of Metidja, more frequently behind the 

 first chain of the Atlas ; but the desert of Sahara is its favourite habitat, and 

 there it is seen in immense numbers. — On the flat grounds they are a match for 

 the Jackals, which cannot approach them with impunity ; in the mountains, on 

 the contrary, they carefully avoid the Jackals. — Translated and abridged from 

 the " Annales des Sciences Naturelles," Sept. 1836. 



3. On Parasitic Larvae. — A paper on this subject was laid before the Aca- 

 demie des Sciences, in July 1836, by M. L. Dufour. One circumstance related 

 in it deserves especial attention. It is an instance of parasitism the singularity 

 of which is calculated to excite the curiosity of the physiologist, and is furnished 

 by a larva supposed to be of the order Diptera, living in the abdominal cavity of 

 Andrena aterrima, a hymenopterous insect. It is sometime since M. Dufour 

 described a larva (that of Ocyptera bicolor), which imparts to the Pentatome, of 

 which it is a parasite, a cavity appropriated exclusively by itself, and which 

 becomes the only aperture whereby the air can reach its respiratory apparatus. 

 This anatomical usurpation is certainly remarkable. But it is quite another 

 thing with the parasite larva of Andrena. This larva lodges itself in the great 

 tracheal vessel at the base of the abdominal cavity of hymenopterous insects. It 

 is fixed there by means of two similar tracheal tubes, both ramifying into its body. 

 This double trachea is furnished by the large bladder of which it is the continua- 

 tion. — This unusual case of parasitism, this example of two insects of widely 

 different genera — one grafted upon the other, by the most important organic 

 apparatus, that of the circulation — constitutes a fact hitherto unheard-of in the 

 annals of science ; and M. Dufour observes, that nothing at all analogous to it 

 is known, except the utero-fcetal circulation of the larger animals — and even be- 

 tween these two phenomena there exists an immense difference. — Bibliotheqve 

 Universelle de Geneve. 



4. — Notes on Viviparous Serpents. — One of my friends, says Mr. Samuel 

 Woodruff, having killed a large water serpent (Coluber sipedon, Less.) came to 

 inform me that it was full of young. On opening its body, I found in its sto- 

 mach two moderate sized Toads, and several insects and larva?. Distinct from 

 the stomach and the other viscera, but contiguous, and only separated by a thin 



