Order COLEOPTERA. 



The Coleoptera or Beetles are chiefly characterized by having the 

 anterior pair of wings, commonly called the elytra, more or less 

 horny or leathery (more often the former) and, as a rule, but by no 

 means always, fitting closely down the back with a straight suture. 

 These elytra are not adapted for flyingy-although they evidently 

 help to support the insect in the air, but serve as sheaths for the 

 posterior pair of wings (commonly spoken of as the wings) which 

 are usually large and ample, and in flight extend far beyond the 

 elytra, beneath which they are more or less elaborately folded when 

 at rest. In many cases the wings are much reduced, and are 

 often quite rudimentary ; very few beetles, however, are absolutely 

 wingless, except such forms as the females of Brilus, Lamjoyris, 

 and Pachypus, which are destitute of both wings and elytra. In 

 cases where the wings are aborted and rudimentary (as in Carabus, 

 etc.), the elytra are often fused together at the suture, and the 

 whole of the upper surface of the hinder portion of the body is 

 practically covered with a solid mass of chitinous material. 

 Darwin's remarks on the species with aborted wings are well 

 known to most of us, but may be quoted again with advantage. 

 In speaking of the beetles of Madeira he says : — " Mr. Wollaston 

 has discovered the remarkable fact that 200 beetles, out of the 

 550 species (but more are now known) inhabiting Madeira, are so 

 far deficient in wings that they cannot fly ; and that, of the 

 twenty-nine endemic genera, no less than twenty-three have all 

 their species in this condition ! Several facts, namely, that beetles 

 in man} r parts of the world are frequently blown to sea and perish ; 

 that the beetles in Madeira, as observed by Mr. Wollaston, lie 

 much concealed, until the wind lulls and the sun shines ; that the 

 proportion of wingless beetles is larger on the exposed Desertas 

 than in Madeira itself ; and especially the extraordinary fact, so 

 strongly insisted on by Mr. Wollaston, that certain large groups 

 of beetles, elsewhere excessively numerous, which absolutely 

 require the use of their wings, are here almost entirely absent *, 

 these several considerations make me believe that the wingless 

 condition of so many Madeira beetles is mainly due to the action 



* Darwin does not allude to one of the most striking facts recorded by 

 Wollaston, viz. -.—that numerous genera {Loricera, TrecJms, Hydrobius, etc.) 

 which are usually winged, are almost entirely apterous in Madeira ; nor to the 

 inexplicable exception of Pristouychus, which has ample wings, although in other 

 countries they are usually obsolete. (Wollaston, Insects of the Madeira 

 Islands, p. xii). 



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