INTRODUCTION XI 



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

 presenting therefore a serrate outline on the inner margin ; the 

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

 forming a serrate club ; the form varies by insensible gradations 

 (as in the family Clerida?), from the regularly serrate form and 

 the very flattened serrate club, to the small and more compact 

 club of Corynetes ; whereby we pass to the next type. Other 

 variations of the serrate type are : — 



a. The joints are short, and very much prolonged on the inner 

 side, giving the pectinate, or on both sides, giving the bipectinate 

 form ; when these prolongations are very long compared with the 

 antenna?, the Jlabellate form results. 



b. The joints emit from the base or apex, sometimes on one, 

 rarely on both sides, cylindrical branches ; the antennae are then 

 called ramose ; if the branches are very long and flexible, they 

 are called plumose. 



3. Clavate, where the outer joints are more or less enlarged, 

 but not triangular, nor leaf-like. This is one of the most usual 

 forms of antenna?, and its modifications connect insensibly with 

 all the other types ; names are therefore necessary for the purpose 

 of more definite description. The principal forms are as fol- 

 lows : — 



a. Moniliform or granose, when the joints, not differing greatly 

 in size, are rounded, resembling a string of beads ; this leads to 

 the filiform type. 



b. Clavate, where the outer joints are gradually larger, forming 

 an elongate club. 



c. Capitate, where the outer joints are suddenly larger, forming 

 a compact rounded club ; this leads gradually to the last type, 



4. Lamellate: in this the outer joints are prolonged internally, 

 opposing flat surfaces to each other, which may be brought closely 

 in contact, forming thus a transverse, or rarely rounded, club, 

 supported at one side by the stem of the antenna?. This form 

 obtains in all Scaraba?ida?. 



Antenna? are called geniculate when the second joint is affixed 

 so as to make an angle with the first; the following joints con- 

 tinue in the line of the second. 



Other names have been applied to modifications in the form of 

 antenna?, but they are of rare occurrence in the literature of the 

 science, and are not used in the present treatise. 



