307 



ORDER II TRACHEARIA.* 



THE few animals that constitute this Order breathe 

 not by lungs, but by air-pipes, which either radiate 

 or branch to every part of the body ; these commu- 

 nicate with the air by a single orifice, (spiracle,) on 

 each side : there is no heart, and not more than four 

 eyes, sometimes, indeed, only two. 



Chelifer^ the Book-Scorpion. 



These little creatures which look like Scorpions 

 in miniature, but destitute of a tail, are often seen 

 crawling backwards or sidewise, in old books, insect- 

 cabinets, and dried plants, where they search for 

 minute Insects. They run rather swiftly, and gene- 

 rally with the claws extended. Kirby says, that 

 they are found upon Flies ;J and we once took, in 

 the Southern United States, a specimen of Elater 

 Ocellatus, which was infested with numbers of these 

 parasites. As they were much larger than the mites 

 (Leptus, $c.) which commonly swarm on insects, and 

 presented their prominent pincers, they caused the 

 Beetle to assume a very odd appearance. 



* Tracheae, air-pipes. 



f XjXj, chele, a crab's claw, and tpigu, pliero, to bear. 



J Bridg. Tr. ii. 303. 



