CEStRtDM 



827 



Hypoderma.—A good example of dermal infection is Hypo- 

 derma bovis de Geer, which infests cattle. The eggs are laid on 

 the skin of the animal, and are probably transferred to the mouth 



Fig. 418. — CEstvus ovis Lin^t^us: Female. (X4.) 



by licking, whence they pass via the oesophagus to the skin, in 

 which they form tumours. It is found in Europe and America, 

 and Peiper has gathered together histories of several cases in 

 which Hypoderma bovis and H. diana Brauer 

 have occurred in man, but this is very rare. 

 The larva which is commonly found in man 

 belongs to Dermatobia cyaniventris, which is 

 described below. 



(Esfrus. — Rhinal myiasis is exemplified by 

 CEstrus ovis Linnaeus, 1761, which has been 

 found several times in the nasal cavities of 

 man, though usually found in sheep. The egg 

 is laid in the nasal cavity, in which the larvae 

 live until they become pupae, 



Gastrophilus. — Intestinal myiasis is exem- 

 plified by Gastrophilus equi Fabricius. The 

 eggs are laid on the skin, often about the knees, 

 and transferred to the mouth, and so to the 

 stomach, by licking. In this organ they live 

 on the secretions and contents; but though 

 they do not bite the mucosa, they cause 

 irritation. In due course they pass out of the ^^^^/^^T'J'y'^f^LiN^ 

 alimentary canal with the faeces, and then n^us. (x 4-) 



