ACARINA. 177 



The Mites are generally very minute, and many 

 are parasites upon larger animals. 



Order AC AETNA. 



Breathing by radiating air-pipes, which open 

 by two spiracles. Body undivided, or only super- 

 ficially divided into thorax and abdomen. Mouth 

 forming a beak or sucker with lancet-like jaws, 

 and palpi (feelers) which are either clawed or 

 fanged. 



HalaracJine (Allman). Palpi free, thread-shaped ; 

 jaws two -clawed ; legs with the last joint terminated 

 by two hooks, and an intermediate three-lobed 

 wart ; body entire, lengthened, sub-cylindrical, 

 furnished with a dorsal plate in front ; eyes none* 



H. halichoeri. Fig. 332 ; mag. f . 

 Halacarus (Gosse). Body covered above with 

 a shield ; beak bulbous, pointed ; palpi tipped with 

 a fang- like claw ; feet formed for walking, directed 

 two pairs forward and two backward, tipped with 

 a pair of hooks ; thighs remote from each other. 



H. rhodostigma. Fig. 333 ; mag. * 

 ctenopus. 



N 



