oa Journal of the Entomological Society of Southern Africa - Notes on acridid anatomy
While making a series of ventral dissections of Zonocerus elegans Thunb., I observed that the relative proportions of the ventral mesothoracic sclerites are very different in the two sexes. The breadth of the anterior margin of the basisternum is markedly less in the males than in the females. This difference is an expression of the fact that the sternal apophyses arise nearer the midline in the males than in the females. The phenomenon may be expressed in quantitative terms by the ratio of the breadth of the sternellum, at the level of the anterior margin of the basisternum, to the breadth of the anterior margin of the basisternum (Fig. 1a, x/y): for brevity this may be referred to as the basisternal ratio. The mean value of this ratio was found to be 1.95 in a sample of 41 males compared with LIB in a sample of 19 females, giving a male:female ratio of 1.65.
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