EYES OF INSECTS. 83 



smooth waters, each of the eyes is, as it were, divided into 

 an upper and a lower half: the one for looking up into the 

 air, the other for looking down into the water. Those of the 

 Harvest Spider are seated at the top- of the head, of all posi- 

 tions the most convenient for a creature living chiefly among 

 grass or stubble. In a common Spider, the eyes, which are 

 all of the simple kind, are no less excellently calculated by their 

 varied positions, front, top, and side-ways, for commanding 

 that range of sight so useful, especially in the hunting tribes, 

 for perception and seizure of their prey. 



Of eyelids, Insects, we believe, are wholly destitute, but they 

 are often amply provided with eye-lashes, or with what stands 

 them in the stead of those protective appendages. Their pur- 

 pose in defending the concave surface of the eye from dust and 

 various injuries is supplied by an assemblage of hairs, with 

 which the cornea of Bees and many other Insects is over- 

 spread : the hairs which spring from its reticulate divisions 

 having been likened, when viewed microscopically, to a forest 

 of fir-trees. 



Linnaeus and other naturalists have doubted whether Insects 

 hear, although, from common observation, as well as from 

 general evidence, their hearing would seem as little a matter of 

 question as their sight. Their aural organs would appear less 

 decidedly ascertained. It is, however, usual to suppose that 

 these are none other than the antenna, those slender flexible 

 appendages, capable of being directed, like the long movable 

 ears of an ass or a hare, to all quarters, for the conveyance of 

 sound. 



Observations, such as may be multiplied daily by ourselves, 

 have also tended to confirm the above inference founded on 

 analogy. Kirby adduces, among other examples, the common 

 use made by those prying parasites, the Ichneumon Flies, of 

 their long, flexible, ever-moving antennae, which they are 

 accustomed to plunge into the deep nest-holes of the solitary 

 Bees, whose grubs are converted into living receptacles for 



