28 MORE MINOR HORRORS 



this. But it does more : its attacks materially 

 lessen the value of the beef which potentially 

 lies beneath the hide, and thus in a double sense 

 the warble-fly is the enemy of man whether 

 he be soldier or sailor. Further, its attacks 

 seriously lessen the milk-supply of the 

 country. 



Amongst the numerous families into which 

 the true flies (Diptera) are divided, none are 

 more harmful to human enterprise than that 

 of the Oestridae, or bot-flies, inasmuch as 

 every single species and every single member 

 of this family passes its larval stage within 

 the tissues of some vertebrate host, and fre- 

 quently in those of domesticated cattle ; some- 

 times even in man himself. One of the 

 commonest genera of this family of flies is 

 Hypoderma, which is represented in our 

 islands, and in many other parts of the world 

 where domesticated cattle are reared, by two 

 species — H. hovis and H. lineatum, both com- 

 monly known as bot- or warble-flies. 



The harm caused by these larvae, living 

 as they do in the tissues of the body, beneath 

 the skin, by piercing holes through the integu- 

 ment or skin, whereby they make their exit 

 from the ' warble ' or subcutaneous tumour 

 in which they have passed their latest larval 

 stage, is almost incalculable. 



Miss Ormerod, who for so many years 



