LETTER V. 



INJURIES CAUSED BY INSECTS. 



INDIRECT INJURIES. 



HAVING detailed to you the direct injuries which we suffer from insect?, 

 I am now to call your attention to their indirect attacks upon us, or the- 

 injury which they do our property ; and under this view also you will own, 

 with the fullest conviction, that they are not beings that can with prudence or 

 safety be disregarded or despised. Our property, at least that part exposed to 

 the annoyance of these creatures, may be regarded as consisting of animal 

 and vegetable productions, and that in two states ; when they are living, 

 namely, and after they are dead. I shall therefore endeavour to give 

 you a sketch of the mischief which they occasion, first to our living animal 

 property, then to our living vegetable property ; and, lastly, to our dead 

 stock, whether animal or vegetable. 



Next to our own persons, the animals which we employ in our business 

 or pleasures, or fatten for food, individually considered, are the most valu- 

 able part of our possessions and at certain seasons, hosts of insects of 

 various kinds are incessant in their assaults upon most of them. To begin 

 with that noble animal the horse. See him, when turned out to his pasture, 

 unable to touch a morsel of the food he has earned by his labours. He 

 flies to the shade, evidently in great uneasiness, where he stands continually 

 stamping from the pain produced by the insertion of the weapons sheathed 

 in the proboscis of a little fly (Stomoxys calcitrans) before noticed as attack- 

 ing ourselves. 1 This alights upon him sometimes in one place and some- 

 times in another, and never lets him rest while the day lasts. See him 

 again when in harness and travelling. He is bathed in blood flowing from 

 innumerable wounds made by the knives and lancets of various horse-flies 

 (Tabanus L.), which assail him as he goes, and allow him no respite 2 ; 

 and consider that even this is nothing to what he suffers in other climates 

 from the same pest. In North America, vast clouds of different species 

 so abundant as to obscure every distant object, and so severe in their bite 

 as to merit the appellation of burning flies cover and torment the horses 

 to such a degree as to excite compassion even in the hearts of the pack- 

 horsemen. Some of them are nearly as big as humble-bees ; and, when they 

 pierce the skin and veins of the unhappy beast, make so large an orifice 

 that, besides what they suck, the blood flows down its neck, sides, and 

 shoulders in large drops like tears, till, to use Bartram's expression, " they 

 are all in a gore of blood." Both the dog-tick and the American tick 

 before mentioned, especially the latter, also infest the horse. Kalm affirms, 

 that he has seen the under parts of the belly, and other places of the body, 



1 See above, p. 25. 



2 Once travelling through Cambridgeshire with a brother entomologist in a 

 gig, our horse was in the condition here described, from the attack of Tabanua 

 rusticus. 



