SENSES OF INSECTS. 325 
The antennex are, in the locust, organs of smell, The 
palpi are probably only organs of touch. It has been shown 
by F. Will that wasps have the sense of taste, and that 
minute gustatory organs are placed near the mouth. These 
organs, in the shape either of pits or projecting bulbs, in 
connection with peculiar nerve-endings, are situated on the 
labium, paraglosse, and on the inner side of the maxilla. 
Similar organs occur in ants. 
Fig. 284.—Longitndina] section of the facetted eye of asphinx: the eye-capsule or 
sclera facetted externally (/), and sieve-like within, shows the rod-like ending of the 
optic nerve-fibres ; X, layer of the crystalline lens; é, iris-like-pigment zone; ch, 
choroid composed of pigment cells ; sz, optic nerve ; ¢7, trachea lost in fine bundles 
of fibrillee.—After Leydig, from Graber. 
The ears are well developed in the locust, and we know 
that the sense of hearing must be delicate, not only from the 
fact that a loud alarum with kettles and pans affects them, 
but the movements of persons walking through the grass 
invariably disturb them. Besides this, they produce a-fid- 
dling or stridulating sound by rubbing their hind legs 
against their folded wing-covers, and this noise is a sexual 
