242 PTILOTA: IMAGO EXTERNAL ANATOMY. 



Plmiinsc, when they resemble a feather (fig. > I . 

 Auricula! e, when one of the basal joints is dilated into a 



shield or ear partially covering the rest (iig. 85). 

 Palmated, when the antenna; are short, broad, and divided 



by deep incisions. 

 Nodose, when they are thickened in various parts, like 



knots. 



Verticillate, when whorls of hair are placed at equal dis- 

 tances upon the joints (fig. 86). 

 Fasciculate, when a bundle of hairs is placed on one side 



of each joint. 

 Scopiferous, when a single or very thick bundle of hair is 



placed upon one of the joints. 



As to their size, antennae are exceedingly variable, as they 

 are also in their length, being sometimes shorter than the 

 head, and at others as long or several times longer than the 

 entire body, especially in the longicorn beetles, whereof Acan- 

 thocinus speculifer, from Brazil, is an example ; in many in- 

 stances they are as slender 

 as a hair, and at other times 

 nearly as thick as the body. 

 As to their direction, they 

 are generally porrccted in 

 front of the head; others 

 throw them over the back ; 

 in some they are stilt', in 

 others flexible ; they are 

 Ac.mh cin, 5p <.c,ife, straight, detlexed, or spiral, 



and are often, when at rest, 



lodged in particular cavities prepared for their reception on 

 the under side of the head or thorax. 



The number of joints of which these organs are composed 

 merits a few observations. Coleopterous insects have in ge- 

 neral eleven joints ; the Heteroptera from four to six ; the 



