ox ANIMAL PAIUSITES. 105 



Another order of the same class, the Mnllcyphaga, or feather and 

 hair eaters, infest various birds, and also the horse and ox, each 

 of them having its own species. Tlie sheep " ked " ought perhaps 

 to be placed in this class. There are other parasites, which, in a 

 popular classification, cannot well be put under any other head, 

 as, for example, the Epizoa, or fish-lice, those small crustaceans 

 which are parasitic upon the bodies of other Crustacea, and on 

 fishes; and the whale-louse (Ci/amus cc^i), which belongs to 

 another order of the Crustacea. 



5. Fleas. 



The fleas (Fulicidce) belong to the order Aijhaniptera. There 

 are two well known species. One is the common flea, Pulex 

 irritans. In its larval stage it is an apodal gTub, which in about 

 twelve days spins a cocoon for itself, and becomes a quiescent 

 pupa, from which the perfect insect emerges in about a fortnight 

 more. The other flea is even a more troublesome creature. It is 

 the " chigoe" of South America and the West Indies. It penetrates 

 under the skin, generally under the toe-nails, where it leaves its 

 larvae to mature into chigoes, and if not dislodged they occasion 

 very troublesome ulcers. On the sugar estates in British Guiana, 

 I have often seen as many as fifty, out of five hundred coolies on 

 one plantation, laid up in hospital by ulcers from the effects of 

 this very small flea. 



6. Parasitic Flies. 



The parasites of this class belong chiefly to the order Diptcra, 

 which includes the " blow flies " (Mtcsca), the " gad-flies," (Estrida\ 

 and "gnats" {Culeoc), with many others which need not be 

 referred to here. The blow-fly (Musccc xomitoria) is also termed 

 the " maggot- Hy" and the "flesh-fly. The larva of this fly, 

 known as the " maggot " or " fly-worm," and not the fly itself, is 

 the real parasite. It is very troublesome, especially among.st 

 sheep, in sultry and moist weather. The fly deposits its eggs in 

 hot weather on wet or dirty parts of the wool, and the ova are 

 soon hatched, when the " maggots " burrow into the skin of the 

 sheep, and if left unattended to for any length of time, will actually 

 eat the sheep alive. A good remedy for the destruction of the 

 maggot is a combination of one part of oil of turpentine to three 

 parts of oil. The gad-fly {CEstridce) is also known under the 

 names of " cleg " and " bot-fly." Tlie " bot," wdiich is merely the 

 larval stage of various species of gad-fly, is an internal parasite 

 in the horse, ox, sheep, and other animals. The gad-fly attacks 

 the animal, not for the purpose of deriving sustenance, but to 

 deposit its eggs. The common gad-fly of the horse {CEstrus cqui) 

 in this manner deposits its eggs on the coat of the horse, where 



