230 DIPTEEA OR TRUE FLIES. 



three to four weeks. They get on to the sheep either from 

 one sheep coming in contact with another or from the ground, 

 where they may hatch out from the fallen puparia. They get 

 to the sucking lambs from the ewes, and often annoy them 

 immensely. The winter is passed in the puparium stage. 



Eemedies. — This and all sheep external parasites are readily 

 amenable to treatment. Dipping soon destroys all these 

 parasites, but as a rule two dippings are necessary, the second 

 about a month after the first, so as to kill off those hatched 

 from the puparia. 



The Forest or Horse Fly (Hippobosca equina). 



The Forest Fly is only of local importance, as it is seldom 

 sufficiently abundant to be obnoxious except in the New Forest, 

 where it is a terrible pest to horses and cattle, and in parts 

 of North Wales, especially in the Snowdon area, where I 

 have seen it in great abundance, notably in the Pen-y-Gwryd 

 and near Quellyn Lake. It is well known to many of the 

 local drivers.-' The fly is the fourth of an inch long and 

 flatfish in form, with a hard leathery skin, deep brown in 

 colour with paler mottlings ; the head is dull yellowish except 

 on the face, where it has a dark stripe ; the thorax has a pale 

 spot on the scutellum, and yellowish-grey markings along the 

 sides and posterior part ; the abdomen is bristly, brown above, 

 paler brown to grey below ; the two wings are opaque, longer 

 than the abdomen, and have thick brown veins along the costal 

 region; the legs are long and bristly, tawny yellow in colour, 

 and banded with brown. The foot is remarkable, and consists 

 of a pair of large claws, with an appendage on each, outside; 

 there is also a long bristle-like thread coming out beneath the 

 claws, and a curious flap -like process between. These flies 

 use their wings but weakly, only flying on the horse and from 

 part to part of the same animal. They cling to the hairs and 

 ^ Miss Ormerod also records it from Breconshire. 



