Onychopalpida 



37 



While there is much justification for their action on the basis of mor- 

 phology, it seems undesirable to recognize the familial separation that 

 they suggest when so few species are represented in the group, as a 

 whole. Therefore, only the single family Opilioacaridae is recognized 

 here. 



Opilioacaridae With, 1902 

 Figure 32 



Diagnosis: These are medium- 

 sized mites about 1 mm. long, and 

 oval in shape. The hysterosoma 

 has indications of segmentation 

 dorsally, the cuticle is striated with 

 numerous minute pores, a divided 

 tritosternum is present, two eyes 

 are located on each side of the 

 propodosoma, and the setae are 

 simple or feathered. The pedipalps 

 have reduced ambulacral claws 

 while the chelicerae are unmodi- 

 fied and a radula-like organ with 

 recurved teeth is situated between 

 and hidden by the chelicerae. The 

 legs are segmented secondarily, 

 trochanters in and iv are divided, 

 the coxae are freely movable, and 

 a pair of unmodified ambulacral 

 claws is present on each tarsus. 

 The genital openings of each sex 

 are ventral between coxae iii, the 

 females have an ovipositor, and 

 the males have specialized areas 

 lateral to the opening. On the dorsal-lateral aspect of the hysterosoma 

 four pairs of stigmata are present, while a median stigma is present in 

 Neocarus. 



Figure 32 Opilioacariis segmentatus 

 With, 1902. Dorsal view of female 

 showing the four pairs of opisthosomal 

 stigmata. (After With 1903) 



Genera 

 1. 



OpilioacarusWiih, 1902 {- Eucarus With, 1903) 

 Type. Opilioacarus segmentatus Wiih, 1902 

 Neocarus Chamberlain and Mulaik, 1942 

 Type. Neocarus texanus Chamberlain and Mulaik, 1942 



