(du. a. C. OUDEMANS) LIST OF DUTCU ACARI. 249 



10. Arrenurus Dug. 1834. So the name of the genus must 

 be written and not Arràenuriis , as has been done by Snellen 

 VAN VoLLENHOVEN (Gelede Dieren van Nederland, p. 74.) and by 

 Neuman (in Kong. Sv. Vet. Akad. Handl. 17. 3. p. 4, 19, 76.). 



11. Tachygaster Lebert 1879 must be changed into another 

 name as this name is already used in 1803 by Meigen for some 

 Dìptera^ in 1817 by Germar for some Coleojifera, in 1840 by 

 Gray for some Ech'modermata , and in 1847 by Giebel for some 

 Pisces. 



12. — Atax Koch. — As te genus Atax of Duces (non Fabr.) 

 is quite another one as that of Koch (this one having Alaxfreniger 

 as type) , the name Atax Kocn must be changed into another. 

 I have not had the opportunity to consult Haldeman's Zoological 

 Contributions, nor have I found any description of this genus, 

 but I presume that it is synonym to Koch's Atax, or better said 

 tliat the type of the genus Unionicola Hald. and the type of the 

 genus Atax Koch are still at present considered as two species of 

 the same genus. If so, the genus Atax Koch must be called 

 Unionicola. If not, then the genus should be called Neumania 

 Lebert, as Lebert's type Neumania nigra is synonym to Atax 

 spinipes Müll, 



As I halve not yet been able to consult all the works on Hy- 

 drachnellae, purposely I have not given descriptions and names to 

 the most probably new species of ÌÌ y drachnellae enumerated above 

 in my list, nor new names to replace those which, as I have 

 pointed out in my « remarks », must be rejected. 



Arnhem, 

 March 15, 1897. 



