52 NATURAL HISTORY 'OF SELBORNE 



side-fly y from its running sideways like a crab. It creeps 

 under the tails, and about the groins, of horses, which, at 

 their first coming out of the north, are rendered half frantic 

 by the tickling sensation ; while our own breed little 

 regards them. 



The curious Reaumur discovered the large eggs, or 

 rather pupce, of these flies as big as the flies themselves, 

 which he hatched in his own bosom. Any person that 

 will take the trouble to examine the old nests of either 

 species of swallows may find in them the black shining 

 cases or skins of the pupce of these insects ; but for other 

 particulars, too long for this place, we refer the reader 

 to ' UHistoire d'Insectes' of that admirable entomologist. 

 Tom. iv., pi. ii. 



sheep-tick is wingless from its birth. We thus get in the family a series of forms 

 starting with the fully winged forest-fly, and leading through the swallow-tick, 

 with its reduced wings, and the deer-tick which has the strange faculty of dropping 

 these organs, to the sheep-tick, which has entirely lost them. Touching their 

 development, it is remarkable that only a single young one is produced at a time, 

 and this, instead of being laid in the egg or larval stage, remains within the 

 mother, nourished at her expense by means analogous to those which obtain in 

 the higher mammals, and when born has either already passed into the pupa stage 

 or immediately assumes that condition. [R. I. P.] 



