CHAPTER VII 



The Suhordei^ Sarcoptifoimes Renter^ 1909 



STIGMATA are not present but some possess a tracheal system 

 opening through porose areas on various parts of the body. The 

 coxae form apodemes beneath the skin on the venter of the body. The 

 cheUcerae are usually scissors-like, for chewing, with strong chelae; a 

 few have specialized or modified chelicerae. The palpi are simple. 

 Pseudostigmatic organs may or may not be present. Anal suckers are 

 often present in the male. 



The Sarcoptiformes are divided into the Acaridiae and the Oribatei, 

 the former containing the cheese mites, itch mites, and feather mites, 

 and the latter the oribatid mites. Although the two groups can be sepa- 

 rated rather easily, their relationship is close and they possess many 

 characters in common, such as body shape in many of the genera, 

 mouth parts for chewing, arrangement of coxal plates, and the Clapa- 

 rede organ which is to be found in larvae of both groups. 



Key to the Sarcoptiformes 



1. Weak skinned, nonarmored; without pseudostigmata and promi- 

 nent clublike pseudostigmatic organs (exception: Pediculocheli- 

 dae); tarsi with caruncles; sexual dimorphism at times strongly 

 marked; many males with copulatory suckers on tarsi or anal 

 region Acaridiae 



Leather-like or strongly sclerotized; usually, with only a few ex- 

 ceptions, with prominent clublike pseudostigmatic organs; tarsi 

 without caruncles; sexual dimorphism not marked Oribatei 



ACARIDIAE LATREILLE, 1802 



The gnathosoma is usually visible from above, rarely being con- 

 cealed within a camerostome. No stigmata or tracheae are to be found. 



320 



