Ìi4 (dr. a. C. OUDEMAîfs) LIST OF DUTCH ACARI. 



don's Mag. Nat. Hist. IV. p. 538). But Walckenaer already gave 

 in 1805 the name Philodronms to a genus of Araneidae , so that 

 another name must take the place of P/dlodromus Jenyns. — 

 Koch created , 4 836 , a genus Tydeus with Tydeus velox as type. 

 (Deutschl. Crust. Myr. u. Arachn. Heft 4, n^. 11). — Since, 

 however, Berlese, 1881, (Att. R. 1st. Ven. Sc. Lett. Art. (5) 

 VIII , p. 43) has shown that Acarus Umactim of Schrank is only 

 a nympha of Tydeus velox of Koch, or properly speaking, that 

 they are only two different stages in the life-history of one and 

 the same animal ; thus it is obvious that this animal must be 

 called Tydeus limacum Schrank (Insecte des limaçons Reaum, 1710, 

 in Mém Acad. Sc. Paris.) (Mite de Limas de cave Joblot, 1754, 

 Observ. bist. nat. I, p. 21. Tab. 8.) (Pou du limaçon , Lyonet in 

 Mém. Mus. Par. XVIII. p. 280. t. 13. f. 13, 1829) {Uypopns 

 limacum Duo. in Ann. Sc. Nat. (2) I. p. 37, 1834) Dermanissus 

 helicis CtERV. Hist. nat. Ins. Apt. Ill, p. 224 , \SU) {Tydeus velox 

 Koch). 



3. {Tydeus\ In consequence of the foregoing statement, all the 

 other species of the genus Tydeus of Koch do remain together 

 in a genus, which cannot bear the name gf Tydeus , as this name must 

 necessarily be restricted to its type : Tydeus velox ; so that an 

 other name should take here the place of Tydeus. 

 , 4. TromMd'mm celer Herm. — This species is considered by 

 Duces as synonym to his Megamerus celer, and afterwards this 

 supposition is repeatedly copied by different authors, without making 

 any objection. On comparing however Duces description and figure 

 of Megamerus celer with those of Hermann's Tromhidmui celer it is 

 obvious that the suggestion of Ducks was totally wrong. My opinion 

 is, tlial Hermann's Tromhìdìum celer is allied to Koch's Tydeus 

 celer rimus and Tydeus sultilis. 



5. Ewjiodides Koch. — This group has afterwards been called 

 Eupodidae by Grube in 1859, Eupodoidae by Thorell in 1871, 

 Enpodiui by Canestrini and Fanzago in 1877, and Megameridae 

 by Kramer in 1877. 



6. Eupodes Koch. — The genus Megamerus of Duces with 



