Sept., 1909.] 



EwiNG : New American Oribatoidea. 



117 



Cephalothorax hinged to abdomen and capable of being folded 



down on the ventral surface of the same ; body compressed ; without tracheae ; 

 mandibles very large and prominent ; palpi of four segments ; integument often 

 brittle and thin ; legs very stout Hoplodermid^.. 



Cephalothorax not hinged 



to abdomen but firmly and immovably 

 attached to the same ; body often de- 

 pressed ; with tracheae opening at the 

 acetabula of the legs; mandibles 

 small ; palpi of five segments ; integu- < 

 ment well chitinized and usually stout ; 

 legs often long and slender. 



Abdomen with chitinous 



wing-like expansions called pteromor- 

 ph£e, which are often capable of being 

 folded over the flexed legs ; legs never 

 enlarged or thickened ; integument 

 usually smooth and shiny. 



Oribatid.1£. 



Abdomen without wing-like 



expansions ; segments of legs some- 

 times thickened or swollen ; integu- 

 ^ ment often rough NoTHRiD^. 



Family ORIBATID.^. 

 Genus PELOPS C. L. Koch. 



Mandibles long, styliform and terminating in minute chel« ; ab- 

 domen sometimes pitted or sculptured and often provided with a rect- 

 angular projection from the anterior margin ; hairs of body spatulate. 



Up to the present time only two species of this genus have been 

 found in America. In Europe the genus is rich in species. 



Key to Species. 



1. Abdomen with prominent spatulate hairs on its posterior aspect. 



P. laticuipidatus sp. nov. 



2. Abdomen hairless except for the large pair of anterior marginal hairs. 



P. bifurcatus sp. nov. 



Pelops laticuspidatus, new species. (Plate II, Figs. 1 and 2.) 



Body chestnut brown ; legs paler than the body. 



No projection from the anterior margin of the abdomen over the cephalothorax. 

 Cephalothorax rather small ; as broad as long. Lamella as long as the cephalo- 

 thorax, of about uniform width throughout. The anterior two fifths of the lamella is 

 free and corresponds to the lamellar cusp of most species; translamella about one 

 half as broad as the lamellae and about twice as long as it is broad ; prominent lat- 

 eral lamella also present. The lateral lamellae are triangular in shape, being pointed 

 anteriorly and bearing a stout, curved pectinate bristle. Lamellar hairs three fourths 

 as long as lamellae, curved and finely pectinate. Pseudostigma slightly projecUng ; 

 pseudostigmatic organ with small, short peduncle and large subcapitate head, which 



is truncate at the end. 



Abdomen subglobose ; ptermorphre not projecting beyond the anterior margin 

 of abdomen. Dorsum with several clavate hairs including two pairs situated at the 

 tip ; the upper pair being about twice as long as the lower pair. 



