310 Mr. A. D. Michael on the 



d'Hist. nat. a])pliquee aux Arts,' vol. xvi. p. liiO, he simply 

 says that he has carried to the genus Orihata A. coleoptriiliif 

 and A. geniculatus of Linnaius, puttin-i^ A. cole.optratas 

 first; and in 1804, in Hist. Nat. dcs Crint. et des Insectes, 

 t. vii. p. 400, he says: "We have made known the f^enis 

 Orihata by describing the Acaras corticalis of de Geer." 

 Latreille no doubt thought that the A. geni'cu/atus of Linnteus 

 was the same species, but really it was not. Even if Latreille 

 had told us in all his works tliat A. geniculatus, Linn., was 

 the type of Orihata, it would not have been gooJ, firstly, 

 because he could not make it the type of Oribata in 1802 

 when he had already made it the type of Acarus in 171)6, in 

 'Piecis des Caracieres geiieriques des Insectes disposes dans 

 un Ordre naturel.' As to this, Dr. Oiidemans says that 

 Latreille created a genus Acarus with Acarus geniculatus, 

 Linn., as type, " but that as Acarus was already preoccupied 

 by Linruvus with Acarus siro, Linn., as ty\)ii, Acarus, Latreille, 

 must fall." It does not seem to me correct to say that 

 Latreille created or attempted to create any new genus ; he 

 simply divided the Linnean genus Acarus, which included 

 the whole of the present order Acarina as far as Linmeus 

 knew of it. Having divided off the genus Tyroglyphus with 

 A. siro, Linn., as type, and other genera, he left A. geii'cu- 

 latus as type of the remaining species, for which he retained 

 the generic name of Acarus, a name which has been con- 

 veniently atid properly dropped by modern acarologists 

 because it has been raised into an order, and it was not 

 possible to say what ought to constitute the genus if it were 

 retained. As to A. si7'o, Liini., being the Linnean type, as 

 L>r. Uudemans says, it is difficult to see upon what lie founds 

 this contention. Linnaus does not in any way indicate that 

 it is the type, and neither in the lOih edition (1758) nor in 

 the 12th edition (1767), which are the only two editions 

 of the ' Systema Naturai ' taken as the origin of nomenclatuie 

 by anybody, does A. siro appear as the first species; A.elephan' 

 tinus is the first, then follow other ]xodid;e,and A.siru'is the 

 ]5th. 8econdly, if A. geniculatus had been the type of 0/7- 

 hata, that type would have been bad because it is not possible 

 to say what species the A. geniculatus of Linnaeus was, or even 

 what family it belonged to. The Linnean description was 

 *^ Acarus niger,Jemorum geniculis suh-gluhusus^^ ; this is all, 

 and is manilestly insufficient. What creature, if any, Latreille 

 sup})0;ed tUa A. geniculatus of Linnaius to be it is not possib e 

 to determine ; it certainly was not the creatuic which we now 

 call JJatmcus geniculatus and allot to Linnanis's name, because 

 in 1804, in ' Hist. Kat. gi^'uerale et particuliere d. Crust, et 

 dcs Insectes,' Latreille says that his -1. geniculatus is the same 



