THE EXTERNAL ANATOMY OF INSECTS 



41 



a- 



The Pedicel.— The. pedicel is the second segment of an antenna {b). In 

 some insects it differs greatl}^ in form from the other segments. 



The Cldvola.— The term cla- 

 y^ ,'-' '-.^ vola is applied to that part of 



;■ ^--'' """-,^ the antenna distad of the pedi- 



cel (c); in other words, to all 

 of the antenna except the first 

 and second segments. In some 

 insects certain parts of the cla- 

 vola are specialized and have 

 received particular names. 

 These are the ring- joints, the 

 funicle, and the club. 



Tne Eing-joints. ^In certain 

 Fig. 51.— Antennaofachalcis-fly. insects (e..?., Chalcididse) the 



proximal segment or segments of the clavola are much shorter than the suc- 

 ceeding segments; in such cases they have received the name of ring-joints (c*). 



The Club.— In many insects the distal seg- 

 ments of the antennas are more or less enlarged. 

 In such cases they are termed the club (c^). 



The Funicle. — The funicle (c^) is that part 

 of the clavola between the club and the ring- 

 joints; or, when the latter are not specialized, 

 between the club and the pedicel. 



The various forms of antenna; are designated 

 by special terms. The more common of these 

 forms are represented in Fig. 52. They are 

 as follows: 



1. Setaceous or bristle-like, in which the 

 segments are successively smaller and smaller, 

 the whole organ tapering to a point. 



2. Filiform or thread-like, in which the 

 segments are of nearly uniform thickness. 



3. Mbmliform or necklace-form, in which 

 the segments are more or less globose, suggesting 

 a string of beads. 



4. Serrate or saw-like, in which the segments 

 are triangular and project like the teeth of a saw. 



5. Pectinate or comb-like, in which the seg- 

 ments have long processes on one side, like the 

 teeth of a comb. 



6. Clavile or club-shaped, in which the segments becon3 gradually broader, 

 so that the whole organ assumes the form of a club. 



7. Capitate or with a head, in which the terminal segment or segments form 

 a large knob. 



8. Lamellate in which the segments that compose the knob are extended on 

 one side into broad plates. 



When an antenna is bent abruptly at an angle like a bent knee (Fig. 51) it is 

 said to be geniculate. 



Fig. 52. — Various forms "of 

 antennae. 



