538 



AKTICULATA. 



HKAD AND ETES OF THE BEE AS MAGNI. 

 TIED BY TUB MICROSCOPE. 



poscil ia thirtci'u ; but some of tlieiii are occasionally auialgamated together, or coucealed by the 

 otluTs, 80 as to make it apjiear that fewer segments are present. 



The first (Segment, or tho head, is composed of a single piece, which bears the eyes, the an- 



tennje, and the organs of the mouth. The eyes, whicli are 

 anidiig the most wonderful olyects in nature, arc almost always 

 of tlic kind called compound, that is to say, they consist of a 

 multitude of little hexagonal facets, brought close together on 

 each side of the head, each furnished with a cornea, a lens, a 

 coating of pigment, and a nervous filament, and being in fact a 

 true eye. The number of these minute organs is sometimes 

 most extraordinary. The eye of the common house-fly has 

 four thousand of them ; that of a dragon-fly more than twelve 

 thousand ; that of a butterfly observed by Puget, seventeen 

 thousand three hundred and twenty -five ; and that of a small 

 species of beetle — Mordella — no less than twenty-five thou- 

 sand. In addition to these compound eyes, many insects also 

 possess two or three ocelli, or simple eyes, placed on the head 

 between the large compound organs ; these appear to be 

 very similar in their structure to the individual eyes of which the compound eyes are com- 

 posed. 



The antenna) are usually attached to the front of the head, between the eyes. They are ex- 

 ceedingly variable in their form, and probably vary considerably in function, although their gen- 

 eral office appears to be that of 

 organs of touch.. In some in- 

 stances, however, their confor- 

 mation appears to indicate that 

 they are the organs of some 

 special sense, and the functions 

 of smell and hearing have been 

 attributed to them by different 

 observers. In their most or- 

 dinary and simple form, they 

 are more or less filiform organs, composed of a very variable number of joints. Sometimes they 

 are thickened at the base, sometimes at the apex. In some cases the whole or part of the joints 

 are furnished with one or more processes, bristles, or hairs, giving the entire organ a comb-like 

 or feathered appearance. 



The structure of the mouth in insects exhibits very remarkable modifications, and these are 

 of the utmost importance in the classification of these creatures. In some insects the mouth 

 is formed exclusively for biting; in others, as exclusively for suction; while in others again it 



is fitted for the performance of both these actions ; and 

 the form of its constituent parts of course undergoes 

 corresponding changes ; but the same organs really 

 exist in all, modified in appearance, indeed, so as some- 

 times to be scarcely recognizable. In the bees the 

 organs of the mouth are adapted at once for biting and 

 for suctional purposes, the elongated tongue constitu- 

 ting a tube throug-h which their fluid nourishment can 

 be drawn in. In the butterflies the suctorial organ 

 consists of a long trunk; in the bugs it is a jointed 

 rostrum ; in the diptera, or two-winged flies, a fleshy process, (fee. The wings, legs, and feet are 

 variously adapted to difl"erent species. 



The abdomen consists generally of nine segments ; in some instances these are attached edge 

 to edge, when the abdomen exhibits little or no flexibility ; in other cases, each segment sUdes 



ANTENNJE OP VABIOUS INSECTS. 



MOnTH AND TONGUE OF THE BEE, MAGNIFIED. 



