Trombidiformes 183 



The chelicerae are strong with opposed, grasping chelae. The rhagidiids 

 have two pairs of genital suckers. 



Genera: 



1. Rhagidia Thorell, 1871 (= Scyphius C. L. Koch, 1836 nom. prae- 



occ; — Noerneria Canestrini, 1886) 

 Type. Rhagidia gelida Thorell, 1871 



2. Coccorhagidia Thor, 1934 



Type. Noerneria clavifrons R. Canestrini, 1886 



Discussion: Very little information is to be found on these mites. 

 They are known from Europe and North America, but future collect- 

 ing will probably reveal them to be world-wide in distribution. They 

 appear to be predaceous and, since they are rather common in certain 

 localities, they may play a more important role in the general relation- 

 ship of small insects and mites than has been thought. They live in 

 soil, humus, and moss. Rhagidia pallida Banks is from New York, 

 New Hampshire, and Washington, D.C., and is to be found on the 

 ground under damp boards or stones; R. cavicola Banks is from Mam- 

 moth Caverns, Kentucky; Banks says this species is somewhat common 

 and is often found under stones on which egg masses of the cave spi- 

 der, Anthrobia mammouthia Telkpf. occur. 



Nothing is known of the life cycle of these mites, other than that all 

 stages are somewhat similar in appearance except for the larval forms, 

 which possess only six legs. 



Cryptognathidae Oudemans, 1902 



Figure 123 



Diagnosis: The cryptognathids are small, scarlet-red mites measuring 

 from 0.300 to 0.400 mm. in length. The body is oval and lacks a su- 

 ture between the propodosoma and the hysterosoma. The dorsum has 

 a net-like skin pattern and the skin is punctate. A pair of lenslike eyes 

 is located on each side of propodosoma. The chitinous extensions of 

 the body form a tube which is not closed ventrally and through which 

 the gnathosoma is capable of being extruded or withdrawn into the 

 body. The chelicerae are shearlike while the chelae are small, almost 

 straight, untoothed, and sharp for piercing. No genital suckers are 

 present. 



