LUCANUS AND HISTER. 37 



of their affinity to the Petalocera leads us to examine the na- 

 ture of the genera that form thehnks of connexion. These 

 genera I propose to call osculantia, from their occurring 

 as it were at the point where the circles touch one another, 

 and to distinguish them from genera annectentia, or those 

 serving to unite the family in their own circle. These genera 

 osculantia,— such as Sinodendron, Lethrm, PlatyceruSy 

 and as I suspect, also jEsalus, have in preference to all 

 others a special right to be termed natural, and appear in 

 general to possess a remarkable character, which is the few- 

 ness of species of which they are composed*. I have men- 

 tioned the genus Platycerus as one of these, because it will 

 be easily perceived that its form enters with difficulty into 

 the circle of Thalerophagous Recticera, and is indeed, as 

 Gylienhall well observes'', the connecting link with the 

 Trogositce, to which it approaches in colour, general form, 

 and antennae, though these last are mostly heteromerous 

 insects, without teeth on the anterior tibiae. However, 

 as it is not at present my object to discover where this path 

 might lead me, I proceed to the consideration of the Sa- 

 prophagous Rectdcera. 



There are few entomologists who have not been struck 

 with the general resemblance in manners and appearance 

 between these and the Saprophagous Petalocera ; but no 

 one has attempted to define in what the analogy between 

 them consisted. Soon after Linneeushad instituted the genus, 

 and TplacedHister immediately after -Scflra&^Ms, Scopolisaid 



^ It ought to be observed that this peculiarity is not so remarkable in 

 the genera which connect the two circles of Petaloceramlh each other, ant* 

 therefore it may perhaps belong solely to those singular insects which serve 

 to connect the more discordant groups. 



" Gylieii. Ins. Suec. vol. i. p. 73. 



