74 OF THE SENSES OF 
Cuvier and Dumeril think that the palpi of insects 
are the organs of touch. While in search of food, 
these are used to try every object which they meet 
with. When walking, they are used to feel the 
ground ; while they answer the purpose of hands in 
thescorpion tribe, andsometimesas feet by the spiders. 
Professor Rennie is of opinion, that an important 
organ of touch in insects, which has been altogether 
overlooked by naturalists, is the surface of the wings, 
being minutely furnished with nerves, which appear 
to him expressly formed for that purpose.* He says, 
— It must be this, indeed, which in a great mea- 
sure serves to direct their flight, as the focus of the 
eyes appears, according to our ideas of senses, to be 
too short for the purpose.” The impulses of the at- 
mosphere on the delicate and sensitive organs, may, 
in a great measure, assist, but certainly the eyes are 
the organs by which they direct their course. 
In illustration of this doctrine, the Professor ob- 
serves,— We remarked, for several weeks, near St 
Adresse, in Normandy, a very limited spot, close by 
the sea, to be daily frequented by about half a 
dozen of the Clouded Yellow Butterfly, (Colias 
Edusa, Stephens,) which seemed to make a regular 
circuit, and return again, altogether independent of 
the direction of the wind, against which they often 
made way. Now, as they rose to so considerable a 
height, that they must have lost sight of the ground, 
* Insect Miscellanies, p. 12. 
