The Insect Fauna of Van Diemen's Land. 319 



dennai^). In the family of Byrrhce, the forms peculiar to our 

 northern hemisphere are replaced by the genus 3IicrocIicetes 

 Hope^ (t) which has enriched our collection with one new 

 species. The genus LimnicJms is found in every zone ; one 

 new species from Van Diemen^s Land is extremely similar 

 to our European L. versicolor, Waltl. (riparius Dej.) 



Of the family of Hi/drojoMlce, the waters of Van Diemen^s 

 Land probably contain some species ; for it is a family dis- 

 tributed nearly equally throughout the different zones ; the 

 rivers and lakes of New Holland, however, have as yet been 

 but little examined ; we know of only one genus^ Cercyon, 

 which is found everywhere. 



Of the LameUicorna : — A continent destitute of the larger 

 Mammalia, cannot be expected to produce the more import- 

 ant forms of Coiyrophaga ; thus, while America on the one 

 hand, Africa and East India on the other, are rivals in the 

 number, importance, and the peculiarities of their genera ; 

 New Holland presents few that are valuable, and Van Die- 

 men's Land possesses only Ontlwjphagus and Apliodms, both 

 widely distributed, and rich in species ; of the former genus 

 we have six, of the latter one species, all new, and some re- 

 markable ; — one, OntliopJiagus [promts) has an unarmed head, 

 but a long, spear-shaped horn issuing from the neck-plate, 

 (of the male) and projecting beyond the head in a straight 

 direction. In another species the unarmed head (of the 

 male) is compensated for by longer fore legs. 



Attagenus would then be a fitting name for 2). pelUo : Tiresias for D. serra, and a new- 

 name must be found for the third genus, now known in England as Megatoma. Mean- 

 while, however, I shall employ the English definition. 3Iegatoma distinguishes itself 

 from Attagenus, by the front edge (Rande) of the Prosternum occupying (?) the mouth. 

 Neither Stephens nor Heer, who have adopted the generical definitions of the EngUsh, 

 have characterised them rightly ; hence they confine these definitions to II. undatum, 

 although D. emarginatus Payk. and D. nigripes F. belong here. 



{*) The characteristics of Trogoder-ma are not so much the number of joints in the 

 clubbed antennae, as in their cavities on the under part of the neck plate, which are 

 ■W3.'a.\\xig va. Megatoma. The form of the antennae is different in the different species, 

 those of V.D. Land, are only three-jointed, and club-shaped. 



(+) Trans, of the Entomol. Soc. of London I. p. 12. The species here described is 



