134 SWALLOWS. 



Many species of birds have their peculiar lice ; but the 

 hirundines alone seem to be annoyed with dipterous insects,* 

 which infest every species, and are so large, in proportion to 

 themselves, that they must be extremely irksome and injurious 

 to them. These are the hippoboscce hirundines, with narrow 

 subulated wings, abounding in every nest ; and are hatched 

 by the warmth of the bird's own body during incubation, and 

 crawl about under its feathers. 



A species of them is familiar to horsemen in the south of 

 England, under the name of forest-fly, and, to some, of side- 

 fly, from its running sideways, like a crab. It creeps under 

 the tails and about the groins of horses, which, at their first 



protection, not punishment from him. The sufferings of their broods, 

 when the parents are destroyed, should excite humanity and demand 

 forbearance. I supplicate from the youthful sportsman his considera- 

 tion for these most useful creatures. The positive good they do, the 

 beneficial services they perform for us, by clearing the air of innumer- 

 able insects, ought to render them sacred, and secure them from our 

 molestation. Without their friendly aid, the atmosphere we live in would 

 scarcely be habitable by man. They feed entirely on insects, which, if 

 not kept under by their means, would swarm and torment us like another 

 Egyptian plague. The immense quantity of flies destroyed in a short 

 space of time by one individual bird is scarcely to be credited by those 

 who have not actual experience of the fact. I was once present when a 

 swift was shot I may as well confess the truth I myself (then a 

 thoughtless youth) the perpetrator of the deed : I acknowledge the fault 

 in contrition, and will never be guilty of the like again. It was in the 

 breeding season, when the young were hatched, at which time the parent 

 birds, it is well known, are in the habit of making little excursions into 

 the country, to a considerable distance from the breeding places, for the 

 purpose of collecting flies, which they bring home to their infant progeny. 

 On picking up my hopeless and ill-gotten prey, I observed a number of 

 flies, some mutilated, others scarcely injured, crawling out of the bird's 

 mouth ; the throat and pouch seemed absolutely stuffed with them, and 

 an incredible number was at length disgorged. I am sure I speak \\athin 

 compass when I state, that there was a mass of flies, just caught by this 

 single swift, larger than, when pressed close, could conveniently be con-, 

 tained in the bowl of an ordinary tablespoon ! Thus was a whole brood, 

 of young birds deprived of one of their nursing parents, by an act of the 

 most wanton cruelty. " ED. 



* This insect is the craterina hirundines of Olfers, which has the 

 instinct to deposit its cocoons in the well sheltered and warm nest of the 

 swallow tribe, heat being so necessary to its existence. The fly, when 

 hatched, lives by sucking the blood of the swallow. So tormenting are 

 these insects to swallows, that they sometimes render the poor animals 

 quite stupid, and unfit for their aerial excursions. Thfe hippobosca equina, 

 is the insect which sucks the blood of horses, and known in England by 

 the name of the forest-fly : it belongs to the same natural family with 

 that above described. ED, 



