400 



Reference: 

 Grandjean, F 



Acarology 



1950. Etude sur les Lohmanniidae (Oribates, Acariens). 

 Archiv. Zool. Exper. et Generale 87(2) :95-161. 



Hypochthoniidae Berlese, 1910 



Figures 323-326 



Diagnosis: None, one, or several transverse sutures divide the dor- 

 sum of the hysterosoma into several sections. The body is weakly 

 sclerotized. The genital plates are usually broader than the anal plates. 



Figure 323 Pterochthoniiis angelus 

 (Berlese). Dorsum of female, detail of 

 propodosomal seta, palpus, clawlike 

 set of ovapositor, and chelicera. 

 (After Grandjean 1950) 



Figure 324 Hypochthoniiis riifidus 

 var. paucipectinatiis Jacot. Dorsum of 

 female. 



Only one egg develops at a time except in Trhypochthonius and Trhy- 

 pochthoniellus where four to six eggs may mature simultaneously. 

 These two genera have been placed in a distinct subfamily — Trhy- 

 pochthoniinae — by Willmann, and into a family by Vitzthum. Grand- 

 jean 1946 divided the Hypochthoniidae into the Hypochthoniidae, 

 Brachychthoniidae, Cosmochthoniidae, and Sphaerochthoniidae, these 

 being based upon the number and location of the transverse sutures; 

 in 1950 he erected the family Pterochthoniidae for Pterochthonius 

 angelus (Berlese), basing it upon the primitive chelicerae, the reten- 

 tion of the preanal segment, the clawlike ovipositor setae, and the 

 large, ornate body setae. This is a primitive mite to be found in west- 



