Page:Jardine Naturalist's library Entomology.djvu/222

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216
SYSTEMATIC ARRANGEMENT.

gate, probably exceeding every other assemblage of the insect tribes. In this country, not more than about fifty indigenous Orthoptera have hitherto been detected, and it is not likely that any considerable number have escaped the researches of modern collectors.

Although these insects must, of course, present a pretty general agreement in all essential parts of structure sufficient to justify their arrangement in the same division of their class, they are certainly very dissimilar in external aspect. The genera Forficula, Blatta, Locusta, and Phasma, bear almost as little outward resemblance to each other as the species of any two separate orders. It was this circumstance that led Dr. Leach to propose its division into three different orders, Dermaptera, including Forficula; Dictyoptera, including Blatta, and distinguished by the tegmina overlapping each other on the back; the other tribes to be referred to Orthoptera. The first of these has been since admitted by some authors to the rank of a separate order; among others, by Mr. Westwood, who names it Euplexoptera, because the term Dermaptera is said to have been completely misapplied by English Entomologists, having been originally proposed for the Cimicidæ. Notwithstanding the peculiarities in its structure which have led to this step, it is difficult, we think, to examine the earwig without being convinced that it is essentially an Orthopterous insect; and as that order must, in any case, be defined with considerable latitude, it can scarcely be regarded as an undue extension of it