34 ORGANS OF THE SENSES. 



upon the crown of the head, where they project like 

 little glass beads. The structure of these eyes is 

 somewhat similar to that of the individual members 

 of the compound eyes ; but as their horny outer lens 

 is far more convex, it is probable that they are em- 

 ployed principally in the examination of objects in 

 very close proximity. 



The seat of the sense of hearing in the majority of 

 insects is by no means determined, although from 

 the behaviour of the creatures, and especially from 

 the fact that many of them are endowed with a gift of 

 noise-making, there can be no doubt that they are 

 also enabled to perceive sounds. Many entomologists 

 maintain the antennae to be auditory organs, and in 

 this view they are certainly supported by the circum- 

 stance that the organ of hearing in the Crab and 

 other Crustacea is situated at the base of one of the 

 pairs of antennae. The organs themselves also, from 

 their structure in many insects, would appear well 

 adapted for the perception of those vibrations in the 

 air by which the impression of sound is produced; 

 but, at the same time, it must be confessed that they 

 must perform some other office in other insects, and, 

 if so, these unfortunates would be deprived of the 

 power of hearing altogether, unless they possessed 

 some special auditory organs. 



But the opinion that it is by means of the antennae 

 that insects obtain the perception of sounds, has been 

 recently still further invalidated by the discovery of 

 what appears to be a genuine ear in several species of 

 Grasshoppers and Crickets, insects which are very well 

 provided with antennae. The ears in these creatures 

 are situated, where perhaps we should scarcely think 

 of looking for them, on each side of the hinder part of 



