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Physical descriptionThese important characters divide the Otiorhynchinæ in a natural manner, and though they cannot be directly observed without breaking up the specimen, as the elytra are frequently more or less soldered together in the apterous forms, yet it is very easy to distinguish the members of the two groups by external minor characters. In the “Otiorhynchinæ apteræ
” there are no prominent shoulders to the elytra; the exposed portion of the scutellum is usually very minute, and scarcely penetrates at all between the exposed parts of the wing-cases; the metasternum is always short; and the part of the mesothoracic episterna left uncovered by the elytra is small or moderate in size. Although this latter point is very variable it is of great assistance in separating the insects of the two groups, and indeed was made use of by Horn as a means of dividing the family.
In the “Otiorhynchinæ alatæ” the shoulders of the elytra are distinct and stand out more or less laterally, the tip of the scutellum separates the exposed bases of the elytra, the metasternum is either elongate or short, and the uncovered part of the mesothoracic episterna is either moderate in size or large.