Hudson. — On the Senses of Insects. 25 



stridulate. At the first sound the male became restless,, 

 extended his antennae, moving them round and round as 

 if to determine from which direction the sound came, and 

 then marched straight towards the female. Will repeated 

 this experiment many times, and with different individuals, 

 but always with the same result. As the male took no 

 notice of the female until she began to stridulate, it is 

 evident that he was not guided by smell. From the manner 

 in which this Cerambi/x was obviously made aware of the 

 presence of the female by the sound, Will considered it clearly 

 proved that in this case he was guided by the sense of hearing. 

 Will has also repeated with these insects the experiments 

 Lord Avebury made with ants, bees, and wasps, and found 

 that they took no notice whatever of ordinary noises; but 

 when he" imitated their own sounds with a quill and a fine 

 file their attention was excited — they extended their antenuae 

 as before, but evidently perceived the difference, for they 

 appeared alarmed, and endeavoured to escape. 



Hicks, in 1859, justly observed that " whoever has ob- 

 served a tranquilly proceeding Capricorn beetle which is 

 suddenly surprised by a loud sound will have seen how 

 immovably outward it spreads its antennae, and holds them 

 porrect, as it were, with great attention as long as it listens, 

 and how carefully the insect proceeds in its course when 

 it conceives that no danger threatens it from the unusual 

 noise." 



Passing now to the organs of vision in insects, we find no 

 difficulty in exactly locating their position. The eyes of these 

 animals" as is well known, are of two distinct kinds — Firstly, 

 the compound eyes, which are made up of an immense 

 assemblage of minute hexagonal eyes usually collected into 

 two large hemispheres situated on each side of the insect's 

 head ; secondly, simple eyes, or ocelli, of which there are a 

 variable number usually situated on the top of the head. 

 The compound eyes are present in almost all fully developed 

 insects, but the ocelli are very frequently absent. In insect 

 larvae and in spiders ocelli are the only organs of sight. 



With regard to the actual power of vision possessed by 

 insects little is known with certainty at present. There is no 

 doubt that some species see much better than others. I re- 

 member specially noticing this when the European blowfly 

 (Calliphora erythrocephala) first appeared in New Zealand 

 during 1888. At that time both the native and introduced 

 species were to be seen resting on fences in the Wellington 

 Botanical Gardens. I experienced considerable difficulty in 

 capturing the European species, owing to its great agility, 

 but could capture the native insect with comparative ease. 

 This circumstance was undoubtedly due to the superior power 



