516 EXTERNAL ANATOMY OF INSECTS. 



lar, though less pronounced knob at their base, inoscu- 

 late in the preceding one; but in some cases the inoscu- 

 lation seems not so perfect, the joints being simply sus- 

 pended by ligament. In pectinated or lamellated an- 

 tennae, the branch is usually a lateral process of the joint 

 from which it issues ; but in Phengodes (Lampyris plu- 

 mosa L.) its involute plumose branches appear to articu- 

 late with the apex of each joint a . I have a specimen 

 of one of the Cleridce, of a genus undescribed, in which 

 each branch is forked. In some tribes of the Capricorn- 

 beetles (StenoconiS) &c.) the antennas are often armed at 

 their apex with spines, sometimes on the upper side and 

 sometimes below. In some aquatic beetles {Gyrinus, 

 Parnus) they are furnished with an auricle at their base, 

 which, like the lid of a box, shuts them in when unem- 

 ployed, and protects them from the water b . 



The portions into which antennas may in general be 

 considered as divided, have been sufficiently explained 

 to you above ; but it may not be amiss to add here a few 

 words on the principal variations in their structure that 

 I have had an opportunity of observing. The scapus c 

 or first joint, which includes the bulbus^ is usually the 

 most conspicuous joint in the antenna (exclusive, I mean, 

 of the capitulum, in those in which that organ terminates 

 in a knob), it being thicker and often longer than the suc- 

 ceeding ones. In the Capricorn and Darkling beetles, 

 indeed {Cerambyx and Tenebrio L.), the third joint is the 

 longest, but the scape is still the thickest; and in the 

 stag-beetles (Lucanus L.), many of the weevil tribes 



a Plate XXV. Fig. 4. 



" Plates XII. Fig. 29 ; and XXV. Fig. 28. a. 



c Plates XI. XIL XXV, k". 



