Chap. 41.] MOTHS, ETC. 41 



which 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 48 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 49 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.) 3I0THS, CANTHAHIDES, GNATS AN INSECT 



THAT BKEEDS IN THE SNOW. 



Dust, too, is productive of worms 50 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, 51 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, 52 when 

 fully developed. These insects, which are venomous, carry 

 with them their antidote ; for their wings are useful in 



48 In c. 32 he has said the same of the grasshopper", in relation to its 

 drink. 



49 A variety of the Cynips of Linnaeus, which in vast numbers will 

 sometimes adhere to the ears of dogs. 



50 These are really the larvae of night-moths. His account here is 

 purely imaginary. 



51 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. 



53 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. 



