38 Acarology 



3. Paracanis Chamberlain and Mulaik, 1942 



Type. Opilioacanis hexopthalmus Redikorzer, 1937 



Discussion: Although opilioacarids are primitive, they, like so many 

 other primitive animals, have speciaHzed characteristics. The radula- 

 like structure in the gnathosoma, the secondary segmentation of the 

 legs, and the divided tritosternum are all considered to be evidence of 

 specialization. 



Opilioacarids are secretive and live under stones and other debris. 

 Chitinous remnants of other arthropods have been found in the gut of 

 these mites. It appears Ukely therefore that they feed, at least in part, 

 on small arthropods. These mites have been found in the Mediterra- 

 nean area and Texas. So few specimens have been collected that rela- 

 tively little is known of their life cycle. They are not known to be of 

 economic or medical importance. 



References: 



Chamberlain, R. and S. Mulaik. 1942. On a new family in the Notostig- 



mata. Proc. Biol. Soc. Washington. 55:125-131. 

 Grandjean, F. 1936. Un acarien synthetique: Opilioacanis segmentatiis 



With. Bull. Soc. Hist. Nat. Afr. Nord. 27:413-444. 

 With, C. J. 1904. The Notostigmata a new suborder of Acari. Vidensk, 



Medd. fra den Naturk. Foren. i. Kbhvn. 1904:137-192 + Pis. iv-vi. 



HOLOTHYROIDEA REUTER, 1909 



The Holothyroidea is represented only by the family Holothyridae. 



Holothyridae Thorell, 1882 



Figure 33 



Diagnosis: The holothyrids are large (up to 7 mm. long) and hemi- 

 spherical in shape but distinctly longer than broad. Evidence of pri- 

 mary segmentation is lacking, and the body is divided into gnathosoma 

 and idiosoma. The deep brown, smooth cuticle is heavily sclerotized 

 in adults, eyes are absent, and the setae are of relatively unmodified 

 form. Tarsal claws and five movable segments are located on the pedi- 

 palps. The chelicerae are chelate. A radula-like organ is present on the 

 tip of the labrum. The legs are all provided with paired ambulacral 

 claws. In the midline between coxae iii and iv is located the genital 



