162 INDIRECT INJURIES CAUSED BY INSECTS. 



sheds its hair, which then stands erect at this time the 

 fly is always fluttering about it, and takes its oppor- 

 tunity to oviposit. The bots remain under the skin 

 through the whole winter, and grow to the size of an 

 acorn. Six or eight of these are often to be found in a 

 single rein-deer that has only seen one winter ; and these 

 so emaciate them, that frequently one third of their num- 

 ber perish in consequence. Even those that are full 

 grown suffer greatly from this insect. The fly follows 

 the animals over^ precipices, valleys, the snow-covered 

 mountains, and even the highest alps ; to which in order 

 to avoid it they often fly with great swiftness in a direc- 

 tion contrary to the wind. By this constant agitation 

 and endeavour to escape from the attack of their enemy 

 they are kept from eating during the day, standing al- 

 ways upon the watch, with erect ears and attentive eyes, 

 that they may observe whether it comes near them a . 

 The rein-deer are teased also by a peculiar species of 

 Tabanus (T. tarandinus) which, by a singular instinct, 

 instead of their skin, makes its incision in their horns 

 when tender. 



Our dogs, the faithful guardians of our other domestic 

 animals and possessions, the attached companions of our 

 walks, and instruments of many of our pleasures and 

 amusements, cannot defend themselves from insect an- 

 noyance. They have their peculiar louse, and the flea 

 sucks their blood in common with that of their master : 

 you must also often have noticed how much they suffer 

 from the dog-tick, which, when once it has fixed itself 

 in their flesh, will in a short time, from the size of a pin's 

 head, so swell itself out by gorging their blood, that it 



* Linn. Flor. Lapp. 379. 



