DIPTERA. 



57 



the thorax grey ; and the abdomen of a reddish yellow, with black 

 spots. The wings are whitish, not diaphanous, with a golden tint, 

 and divided by a winding band of blackish colour. The feet are 

 palish yellow. 



This species is found in France, in Italy, and also in the East, 



Fig. 41. — Horse-fly, m.?\& {CEstrm 

 {gasterophilus) equi). 



Fig. 42. — Horse-fly, female {(Estriis 

 {gasierophilus) equi). 



especially in Persia, and rarely in England. During the months of 

 July and August the (Estriis frequents pastures, and deposits its eggs 

 chiefly on the shoulders and knees of horses (Plate I. ). In order to do 

 this, the female suspends herself in the air for some seconds over the 

 place she ha^ chosen, falls upon it, and with her abdomen bent, sticks 

 her eggs to the horse's hairs by means of a glutinous liquid with 

 which they are provided, and which soon dries. This is repeated at 

 very short intervals. It often happens that from four to five hundred 

 eggs are thus deposited upon the same horse. Guided by a marvellous 

 instinct, the female CEstnis generally places her eggs on those parts 

 of the horse's body which can be most easily touched with the 

 tongue, that is, at the inner part of the knees, on the shoulders, and 

 rarely on the outer part of the mane. 



The eggs of the CEstnis, which are white and of conical form, 



Fig. 43.— Eggs of the Gad-fly {CEstrus {gasterophilus) equi) deposited on the hairs of a horse. 



adhere to the horse's hair, as shown in Fig. 43. They are furnished 

 with a lid, which at the time of hatching opens, to allow the exit of 



