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remarkable that while in certain groups of beetles those species which in- 

 habit places near the sea level are perfectly winged, their near relations which 

 live at high elevations on mountains are frequently furnished with very rudi- 

 mentary true wings or with none at all. 



The Coleoptera are also distinguished from the two orders most nearly 

 related to them in appearance, the Orthoptera and Dermaptera, by the fact 

 of their having, before they acquire their perfect (or imago) state, a well de- 

 fined stage of quiescence — the pupa state, analagous with the same condition 

 in butterflies and moths — in which the perfect insect is soft and yellowish- 

 white, plainly seen through the folds of a thin investing membrane which 

 holds the various limbs closely pressed against the body, and in which stage 

 the only motion of which the insect is capable is of a wriggling character, 

 caused by the movement upon each other of the abdominal segments. Among 

 the crickets, cockroaches, earwigs, and bugs — -which latter differ from the 

 beetles in having a mouth furnished with a proboscis through which they 

 suck the juices of the plants and animals upon which they feed — there is no 

 distinct stage of pupa-hood, but the whole time between the emergence of the 

 larva from the egg and the period when the perfect form is reached is one of 

 continual evolution, the wings and other organs distinctive of the imagal 

 condition, being gradually added during a period of activity, in which the 

 transitions from larva to pupa and from pupa to imago are not or scarcely 

 marked. 



Some knowledge of the external anatomy of beetles is absolutely necessary 

 to one who desires to name the specimens he adds to his collection, and a 

 brief outline of the structure of the principal parts of the perfect insect is 

 here given, for the correct understanding of which, however, one of the larger 

 ground beetles or a large water beetle should be dissected and compared, part 

 by part, with those mentioned. Take, for example, a specimen of Carabus 

 violaceous or Pterostichus niger, both common ground beetles, and with the 

 aid of a lens the following structure will be easily made out. 



The body is composed of three parts, viz. head, thorax, and abdomen. 



The head, which is often narrowed behind into a neck, carries on each side 

 a pair of large compound eyes, each of which is sometimes divided by a pro- 

 cess of the cheek into two portions, one upper and one lower, as in the whirl- 

 wig beetle (Gyrinus natator). Occasionally the head between the eyes, 

 which portion is called the vertex, carries one or two simple eyes {ocelli). 

 The portion in front of the vertex is the forehead ; the extreme front of the 

 forehead, often separated by a distinct joint or seam is called the clypeus. In 

 the common Dor-beetle the clypeus is very distinct, and bears a well-defined 

 tubercle. Springing from each side of the head in front of the eyes, or from 



