THE ACAEIXA OE MITES. 



103 



3. One claw to each tai'siis; ventral apertures slightly separate Eoploderma. 



Three claws to each tarsus; ventral apertures contiguous Phthiracarus. 



Most of our species, as E. sphaerula (fig. 209), have a smooth, shining dorsTim, with a 

 few hairs; but one species, H. granulata Banks, has a very rough dorsum. The char- 

 acters of the species are not as easily obserA'ed as in Oribatidae, and there appears to be 

 considerable variation in size in the same species. 



Family LABIDOSTOIilMATID^. 



This family contains but one genus, Lahidostomma (figs. 211, 212), a few species 

 of which are found in Europe, Central America, and Oregon in fields or among fallen 



Fig. 211.— Labidostomma cornuta. 

 (Original.) 



Fig. 212.— Labidosiomma cor- 

 nuta, venter. (Original.) 



leaves. The mandibles are veiy large and prominent; the coxse are all approxi- 

 mated; the tarsus I is short and ends in two claws, wlule the other tarsi are much 

 longer and end in three claws. The genital and anal apertures are large and close 

 together. The body is rather elongate, depressed, yellowish in color, and without 

 eyes. Their general appearance is that of a Farasitus, but their structure shows they 

 are closely related to the Oribatidae. Trouessart put them in the Gamasidae, Canes- 

 trini and others liave placed them in the Oribatida?, Oudemans made a family for them, 

 and some think they should form a separate suborder — Stomatostigmata. They were 

 first desciibed by Von Heyden as Panoplia, and later by Canestrinias Nicoletia, both 

 names being preoccupied; Labidostomma of Kramer is available; later Canestrini 

 proposed Nicoletiella, and this name is used by some writers. Ewing described our one 

 species as a new genus, Ccratoacarus. The few known species show more or less 

 plainly a pit on each side of the cephalothorax, from which arises a hair or bristle; 

 but it is doubtful if tliis is homologous with the pseudostigmatic organ of the Oriba- 

 tidae. Their habits and immature stages are unknown. Oudemans has found that 



