98 (dr. a. c. otjdemans). notes on acari. 



Classification of the Thrombidiidae. The CoecuUnae, Eupodinae and 

 Bdell'mae are in danger to be separated from the remaining Throni- 

 hidiidae. I will say here some words in favour of their being re- 

 united in the named family. 



CoecuUnae are tolerably hard, well chilinized creatures, provided 

 with a number of dorsal shields; further their 4 fore-legs are armed 

 with enormous thorns directed inward (medianward). A prey thus 

 is perforated. These characters were important enough to a few 

 authors to separate the CoecuUnae from the Thromhïdüdae and to 

 bring them closer to the OpiUonldae. — It is true that these 

 formidable weapens are found too in some Opilionidae^ and that 

 Opilionidae are well chitinized, so that Wie Coeculkiae hediV a Q,ev{d\n 

 resemblance to certain Opilionidae ; we nevertheless consider these 

 facts only as mei'e convergencies, results of the life amoung stones 

 in mountains. Further the same thorns on the fore-legs we find 

 in Coeculosovia, a genus of the thrombidiid Eri/ihraeinae; one or 

 more dorsal shields are found repeatedly in ThromhidUdae, especially 

 in larves, which proves that the presence of shields is a primitive 

 one. The whole organisation of the Coeculus is typical Thromhi- 

 dàd'ie-WVo,. To remove Coeculus from the Thrombidiidae should be 

 the result of sliortsithedness. 



So too a few authois will separate the Eupodinae and Bdellinae 

 from the Thromhidiidae simply because the palps of these animals 

 are not so configurated as those of the remaining Thrombidiidae; 

 their 5th free joint, viz., is not hung on the ventral side of the 4th 

 joint, but it is implanted on the distal end of it — indeed a primitive 

 arrangement — or there are only 4 joints. Even the 4th joint may 

 be absent. But these facts are also found in members of other 

 families oi' subfamilies, e. g. in parasitic forms. If the shape of 

 the palp should be a reason to remove these subfamilies from the 

 other, in how many families we should be obliged to break up the 

 Hydrarachnidae with their at least 7 shapes of palps? I present 

 here a tabi o of the subfamilies, which may be at the same time 

 a «key». 



