Chap. 41.] 
MOTHS, ETC, 
41 
whicli has its head always buried deep in the skin [of a beast], 
and so, living on its blood, swells to a large size. This is 
the only living creature that has no outlet''^ for its food; 
hence, when it has overgorged itself, it bursts asunder, and thus 
its very aliment is made the cause of its death. This insect 
never breeds on beasts of burden, but is very commonly 
seen on oxen, and sometimes on dogs, which, indeed, are sub- 
ject to every species of vermin. With sheep and goats, it 
is the only parasite. The thirst, too, for blood displayed by 
leeches, which we find in marshy waters, is no less singular ; 
for these will thrust the entire head into the flesh in quest of 
it. There is a winged insect^^ which peculiarly infests dogs, 
and more especially attacks them with its sting about the 
ears, where they are unable to defend themselves with their 
teeth. 
CHAP. 41. (35.) MOTHS, CANTHAEIDES, GI>"ATS AN INSECT 
THAT BKEEDS IN THE SNOW. 
Dust, too, is productive of worms^^ in wools and cloths, and 
this more especially if a spider should happen to be enclosed 
in them : for, being sensible of thirst, it sucks up all the mois- 
ture, and thereby increases the dryness of the material. These 
will breed in paper also. There is one kind which carries 
with it its husk, in the same manner as the snail, only that 
the feet are to be seen. If deprived of it, it does not survive ; 
and when it is fully developed, the insect becomes a chrysalis. 
The wild fig-tree produces gnats, known as " ficarii and 
the little grubs of the fig-tree, the pear-tree, the pine, the 
wild rose, and the common rose produce cantharides,^^ when 
fully developed. These insects, which are venomous, carry 
with them their antidote; for their wings are useful in 
*8 Tn c. 32 lie has said the same of the grasshopper, in relation to its 
drink. 
A variety of the Cynips of Linnaeus, which in vast numbers will 
sometimes adhere to the ears of dogs. 
^ These are really the larva) of night-moths. His account here is 
purely imaginary. 
He speaks of the Cynips psenes of Linnaeus, which breeds on the 
blossom of the fig-tree, and aids in its fecundation. See B. xv. c. 21. 
^2 He alludes to various coleopterous insects, which are not included 
among the Cantharides of the modern naturalists. They are first an egg, 
then a larva, then a nympha, and then the insect fully developed. 
