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 Ma.^sif d’Algar 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 fiat grounds they are a match for 
the Jackals, which cannot approach them with impunity; in the mountains, on 
the contrary, they cai^fully avoid the Jackals.— Translated and abridged from 
the Annales d'es Sciences Naturelles" Sept, 1836. 
3. On Parasitic Larv^. —A paper on this subject was laid before the Aca~ 
dcmie 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 Dlptera, living in the abdominal cavity of 
Andrena aterrima, a hymenopterous insect. It is sometime since M. Dufour 
described a larva (that of Ocyptera hicolor), 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-foetal circulation of the larger animals.—and even be- 
t veen these two phenomena there exists an immense difference.— Bibliotkeque 
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 larvae. Distinct from 
the stomach and the other viscera, but contiguous, and only separated by a thin 
