INTRODUCTION. 



XIU 



in our fauna the niinimiiin in Adranes, where there are but two 

 joints, and the maximum in Prionus where 25-27 are seen. The 

 usual number, however, is eleven. 



The basal joints of the antenuic are usually of denser consist- 

 ence tlian the outer ones and less pubescent. In the outer joints 

 will be observed a structure intended for special sensibility, con- 

 vsisting of an immense number of pores, visible only under high 

 magnifying power, and covered by a very delicate transparent 

 membrane. These pores are usually generally diffused over the 

 sui'face of the joints as in most Carabidai and other predaceous 

 Coleoptera, or aggregated in patches as in Zopherus, or confined 

 to the protected parts of the lamellae as in ScarabteidtB. In those 

 genera in which the antenna terminate in an abrupt club, the 

 sensitive surface is confined almost entirely to the club, or even 

 to but a small portion of it, as in some Histeridse and many 

 Rhynchophora. No serious attempt has been made to utilize 

 these variations for the purposes of classification, except by 

 Lacordaire in the Buprestidae. 



The forms of the antennae may be reduced to the following 

 types:— 



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Serrate Antennae and Modifications: 1. Serrate, Ludius; 2. Pectinate, Coryin- 

 bites; 3. Bipectinate, Priouocyphon ; 4. Flabellate, Acneus ; 5. Plumose, Denaroides : 

 6, 7, 8. Irregularly serrate, approaching the Clavicorn type ; U. Dorcatoma ; 7. Aulicus ; 

 8. Corynetes. 



1. Filiform, where the joints are cylindrical, and the outer 

 ones not or scarcely enlarged ; when the joints are gradually more 

 slender to the tip, the antennae are said to be setaceous. 



2. Serrate, where the joints are triangular and compressed, 

 presenting therefore a serrate outline on the anterior margin ; the 

 outer joints (usually three in number) are sometimes enlarged, 



