GENEKAL EXTERNAL STETJCTTJEE OP INSECTS. 11 



the object of all anatomical research, yet the mere study of the 

 structure of the organs alone, their wonderful mechanical adapta- 

 tions, and their modifications in different animals forms a most fasci- 

 nating field in itself, and besides this it gives us an insight into the 

 blood relationships and degrees of kinship existing between the 

 multitudes of animal forms found in nature. In the study of com- 

 parative anatomy we are constantly surprised to find that structures 

 in different animals which at first sight appear to be entirely differ- 

 ent are really the same organs which have been simply changed in 

 a superficial way to serve some new purpose. For example, the 

 front wing of a bee and the hard shell-like wing cover of a beetle are 

 fundamentally the same thing, both being front wings — that of the 

 beetle being hardened to serve as a protection to the hind wing. 

 Again, the ovipositor of a katydid and the sting of a bee are identical 

 in their fundamental structure, differing in details simply because 

 they are used for different purposes. Hence, in the study of anat- 

 omy we must always be alert to discover what any special part cor- 

 responds with in related species. In order to do this, however, it 

 is often necessary to know the development of an organ in the 

 embryo or in the young after birth or after hatching, for many 

 complex parts in the adult have very simple beginnings in an imma- 

 ture stage. 



Thus it becomes evident that the structural study of even one 

 organism soon involves us in the subjects of anatomy, physiology, 

 and embryology, and, if we add to this a studj^ of its senses, its 

 behavior, and its place in nature, the field enlarges without limit. 

 The student of the honey bee realizes that a lifetime might be spent 

 in exploiting this one small insect. 



The differences between animals are much greater on the outside 

 than on the inside. In the descriptions of the organs of the honey bee 

 anyone will know what is meant by the " alimentary canal," the 

 " nervous system," or the '' respiratory system," but the external 

 parts are so different from those of animals with which we are more 

 familiarly acquainted that no general reader could be expected to 

 know what is meant by the names applied. Moreover, the bee and its 

 allies are so modified externally in many ways that, at first sight, 

 their parts look very different even from those of other insects. 

 Hence, we shall give a preliminary account of the external structure 

 of insects in general, for it is hoped that the reader will then more 

 easily understand the special structure of the honey bee, and that the 

 application of the terms used will appear more reasonable to him. 



Since all animals originate in an egg, the change into the adult 

 involves two different processes: One ,is growth, which implies 

 merely an increase in size, the addition of material to material; the 

 other is development, which means change in shape and the produc- 



