12 OOLEOPTEEA OF INDIANA. 



which the antennas end in an abrupt clnb the pores are confined to 

 its surface ; in most cases, however, they are generally scattered 

 over all except the basal joints. 



The principal forms of antennae are as follows: 



(a) Filiform or thread-like, where the joints are cylindrical 

 and the outer ones not or scarcely enlarged. 



(b) Setaceous or bristle-like, where the joints are gradually 

 more slender to the tip. 



(c) Capillary or hair-like, where the joints are long, slender 

 and very loosely united. 



Fig. 3. Serrate antenna and modifications: 1, serrate; 2, pectinate; 3, bipectinate; 4, flabellate; 

 5, plumose; 6, 7, 8, irregularly serrate. (After LeConte and Horn.) 



(d) Moniliform or bead-like, when the joints are of nearly 

 uniform size and rounded, thus resembling a string of beads. 



(e) Serrate or saw-like, when the joints are triangular and 

 compressed, presenting therefore a saw-tooth-like outline on the 

 front margin. 



(/) Pectinate or comb-like, when the joints are short, with 

 their front angles much prolonged. 



(g) Bipectinate, when each joint has a comb-like tooth on each 

 side. 



(h) Flabellate or fan-like, when the prolongations from the 

 joints are very long compared with the antennas, and fold together 

 like a fan. 



(i) Plumose or feather-like, when the prolongations are long, 

 slender and flexible. 



(/) Clavate or club-like, where the outer joints are more or 

 less enlarged, but not triangular or leaf-like. This is among beetles 

 the most common form of antennae, and it grades gradually into 

 most of the other types. 



