insects: theik eaes and eyes. 189 



nearly alike in size and outline, tliat the whole forms 

 an almost straight rod, slightly tapering to the tip. 

 Each joint, however, sends forth two long straight 

 branches, so disposed that the pair make a very acute 

 angle, and the whole double series of seventy on each 

 side, form a deep narrow groove. These two series 

 of branches, being perfectly regular and symmetrical, 

 impart to the antennae the aspect of exquisite feathers. 



It is, however, when we examine the elements of 

 this structiire in detail, using moderately high powers 

 of enlargement, that we are struck with the elaborate- 

 ness of the workmanship bestowed upon them. Each 

 of the lateral branches is a straight rod, thick at its 

 origin, whence it tapers to a little beyond its middle, 

 and then thickens again to its tip. Here two horny 

 spines project from it obliquely, one much stouter than 

 the other, at such an angle as nearly to touch the tip 

 of the succeeding branch. 



Besides this, each branch is surrounded throughout 

 its length with a series of short stiif bristles, very close- 

 set, projecting horizontally (to the plane of the axis of 

 the branch), and bent upwards at the end candelabrum- 

 fashion. The mode in which they are arranged is in a 

 short spiral, which makes about forty-five whorls or 

 turns about the axis ; at least in the branches which are 

 situated about the middle of the antenna ; for these 

 diminish in length towards the extremity, bringing the 

 feather to a rather abrupt point. 



The entire surface of the branch gleams under re- 

 flected light with metallic hues, chiefly yellows and 

 bronzy greens ; which appear to depend on very mi- 

 nute and closely-applied scales that overlap each othei-. 

 The main stem of the feather, — that is, the primary rod 



