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SUPPLEMENT 



to the insect. That an acute sense of touch 

 resides in the antennas, cannot be doubted by 

 any one who has noticed how carefully insects 

 pilot their way with them, and that they 

 never, except when flying, pass from one twig 

 or leaf to another without first testing its 

 security with their horns. 



The annexed cut represents one of the an- 

 tennas of the Bombyx antiqua, highly magnified. 



In the following figure, a portion of the an- 

 tennae is seen vertically, covered with an im- 

 brication of white scales or feathers, under 

 which the pectens issue on each side. 



The head of the Bombyx cnja, exhibiting 

 one antenna?, and the insertion of the other, is 

 represented by the following figure. 



The palpi are small filiform articulated 

 horns, from four to six in number, placed 

 near the mouths of insects. These are usually 

 termed \\\z feelers, as the creature is observed 

 to thrust them in every matter, as a hog 

 would its nose, when in search of food. Some 

 have supposed them to be a provision by which 

 the insect is enabled to hold its food near the 

 mouth. 



The eye 3 of insects are a wonderful piece 

 of mechanism, differing considerably in their 

 construction from those of other animals. 

 " Among the exterior parts of insects, none 

 are more worthy of minute investigation, and 

 very few persons can be found who are insen- 

 sible to the beauties of this organ when ex- 

 hibited under the microscope, which instru- 

 ment alone can point out to us the prodigious 

 art employed in its organization." The eyes 

 of insects differ in different species ; they vary 

 also in number, situation, connection, and 

 figure. " In other creatures they are move- 

 able, and two in number ; in insects, the 

 genus cancri excepted, they are fixed ; they 

 have no eyebrows or eyelids, but the outer 

 coating is hard and transparent. The greater 

 part of insects have two eyes ; some have a 

 larger number varying from three to eight. 

 The eyes of insects are of two kinds : the 

 stemmata, or single eyes ; and the reticulated, 

 or clustered eyes." The stemmata were first 

 noticed by M. de la Hire ; they are three 

 lucid protuberances placed on the back part 

 of the head of many insects : their surface is 

 glossy, of an hemispheric figure, and a coal 

 black colour. Reaumur made experiments on 

 these eyes, and found that when they were 

 covered the insects flew to a small distance 

 only, and apparently at random ; the reticu- 

 lated eyes appear to be adapted only for long 

 vision, and do not give distinct images of 

 objects close at hand^ The reticulated eyes 

 are wonderful structures when examined by 

 the microscope : they are those hemispherical 

 protuberances on the sides of the insect's head, 

 which in the mass are obvious to the unas- 

 sisted eye, and are even seen, without optical 

 assistance, to be composed of a kind of net 

 work. Each protuberance, in its natural 

 state, is a body cut into a number of faces, 

 like an artificial multiplying glass ; but with 

 this superiority in the workmanship, that as 

 there, every I'ace is a. plane, here, every one is 

 convex, immensely more numerous, and con- 

 tained in a much smaller space. If one of 

 these protuberances be taken from the head of 

 the insect, washed clean, and placed before 

 the microscope, its whole structure is seen, 

 and it becomes an object worthy of the highest 

 admiration. Each separate eye is found to 

 have an hexagonal, a quadrangular, or other 

 regular sided figure, varying in size according 

 to its situation in the head, and including a 

 convex, or in point of fact, a meniscus lens, 

 composed of a number of layers, which may 

 be separated by maceration, and subjected tc 

 special examination. 



" The eyes of the libellula, or dragon-fly, 

 on account of their size, are peculiarly adapted 

 for microscopical examination ; and by the as- 

 sistance of the instrument, you will iind that 



