172 EVENINGS AT THE MICKOSCOPE. 



murderous deeds ; and, as of old the axeman held up 

 " the head of a traitor " to public gaze, so I lay this 

 head on the glass of the compressorium for your con- 

 templation. 



And before I apply pressure to the glass-plate, de- 

 vote a moment's attention to the tout ensemble. First, 

 the head itself is a hemisphere, almost wholly occupied 

 with the two compound eyes, which present the beauti- 

 ful appearance of a globe of black velvet, studded with 

 gold buttons arranged in lines crossing each other at 

 right angles. The summit of the head, where the two 

 compound eyes unite, bears a sort of rounded pedestal, 

 the area of which forms the sole part of the head not 

 covered by the organs of vision. On this are placed, 

 side by side, the two antennae, springing from rounded 

 bulbous bases ; they consist of twelve (exclusive of the 

 basal bulb) cylindrical joints, which are beset on all 

 sides with short arched hairs, but have besides a whorl 

 of radiating long hairs surrounding the bottom of each 

 joint. The effect of this is exceedingly light and ele- 

 gant. 



Between these projects a long cylinder, which re- 

 presents the lower lip {labium) ; it slightly swells to- 

 wards the tip, where it forms a round, nut-like knob, 

 covered with exceedingly minute papillae, and no doubt 

 constituting a highly sensitive organ of touch. For 

 the greatest part of its length it is covered with lined 

 scales, and with short arched hairs, like the antennae, 

 while each side of its base is guarded by a labial palp 

 of three joints. 



On applying a graduated pressure, slowly increased 

 to actual contact of the plates (or as near an approxi- 

 mation to it as we can effect), we see first that the nut- 



