268 Acarology 



mera i and ii often with common, rodlike, long process which 

 often reaches subcutaneously far under epimera in or even under 

 iv; posterior margin of epimera iv usually transverse and as a rule 

 without or only insignificant central process, and therefore with- 

 out concave, medial region or genital indentation between coxae 

 or epimera; genital organ usually back of epimeral region; legs i 

 and II frequently thickened in proximal and middle segments and 

 covered with paired, swordlike setae; tarsal claws as a rule simple, 

 sickle-like, and without processes; legs iv of male not usually sexu- 

 ally differentiated Unionicolidae 



Gland pores of skin not conelike; chelicerae separated from each 

 other; palpal segment in without lateral spines; posterior process 

 of anterior epimera short, with hooklike tips, and as a rule not 

 reaching beneath posterior epimera; posterior end of epimera iv 

 with median process, forming genital indentation; genital organ 

 usually close to epimera and removed from posterior margin of 

 body; legs i and ii without conspicuous setae and not thickened; 

 tarsal claws usually forked and with processes; legs in and iv of 

 male usually sexually differentiated Pionidae 



27. Genital suckers lie on more oi less sickle-like plates in deep geni- 

 tal indentation, or the six, eight, or more suckers lie in "lipfields" 

 (exception: $ of Momonia in which suckers are on flaplike plates 

 in partially armored ventral skin) beside or under inner edge of 

 genital rolls which are united with ventral plate; genital organ 

 close to epimera iv, often in deep genital indentation; body in lat- 

 eral view very round; palpal segment ii without protuberances on 

 inner margin; segment iv often with processes on inner margin 28 



Six, eight, or more genital suckers on more or less distinct, round- 

 ish, or ledgelike plate; plates on rear of body, more or less free in 

 male, united with ventral plates; true genital indentation present; 

 body, more or less flat, as a rule distinctly longer than broad; epi- 

 mera often united medianly with one another; palpal segment ii 

 at times with protuberance on inner margin; segment iv with tiny 

 inner setae Axonopsidae 



28. Palpal segment iv shorter than segments ii plus in; genital inden- 

 tation does not reach to epimera i and is either formed by mar- 

 gins of posterior epimeral plates or is entirely lacking; genital 

 suckers lie in "lipfields" at inner margin of flaplike but solid, im- 

 movable genital folds which limit laterally genital opening in ven- 

 tral armor (exception: 9 of Momonia in which folds are narrow 

 and not united with ventral shield) ; body usually disklike and 

 flat 29 



