(de. a. C. OUDEMANS). NEW LIST 01" DUTt'U ACARI, I. 165 



N. lacusiris. On looking at them I was surprised to see the exterior 

 clubs of the pseudo-stigmatic organs, and I have drawn one in a 

 perfect condition in PI. XXX , which had not then gone to press. 

 I think the organs must be looked on as becoming abortive; pos- 

 sibly the time of year may affect the condition, specimens obtained 

 from the same pond in May were without the oi'gans. » 



That I did at first not see the pseudostigmatic organ is , because 

 these animals are generally covered with detritus. All my specimens 

 bear their pseudo-stigmatic organs, contrary to those of Michael. 



Further the tibiae of all the legs bear at their distal ends an 

 enormous tactile hair , much longer than the tarsi with their 

 enormous claws. Michael does not mention nor draws such tactile 

 hairs in his Eremaeiis lacustris. 



I maintain my supposition that my Acarus is identic to Acarus 

 con/ervae Schrank. When the dark coloured animal , wholly covered 

 with detritus is seen with low powers , the demarcation between 

 céphalothorax and abdomen cannot be perceived and the enormously 

 developed tactile hairs at the 8 tibiae immediately strike us, and 

 have evidently struck Schrank too. 



The c( key » on p. 44 of « Das Tierreich , Oribatidae » , is there- 

 fore to be changed as follows: 



Aquatic — ila. 

 ^^' ^ Terrestrial— d 8. 



Psstg. very indistinct ; no true Lam. , but there 

 17äf. ( are two pairs of rather irregular ridges . E. lacustris. 

 Psstg. distinct ; Lam. present E. confervae. 



Eremaeus lanceolatus (Michael). 



Some of my specimens have lamellae I'unning beyond the lamellar 

 hairs, curving at the same lime inward. Some of them even have 

 lamellae which reach one another in the median line, forming a 

 translamella , bowed forward. Therefore change the « key » on page 

 44 of (( Das Tierreich , Oribatidae » as follows : 



