. Smithsonian miscellaneous collections. inated within the lateral wall of the tergum(B, Eps). The prosternum consists of two sclerites in the ventral wallof the segment between the bases of the first legs (fig. 21 A, S, Ss),the anterior one connected by the precoxal bridges (Acx) with thepleura. The prothoracic legs appear to be inserted between the ster-num and the lower edges of the tergum, but the lateral connections of NO. 2 THORACIC MECHANISM OF A GRASSHOPPER SNODGRASS 35 the legs are really with the inflected pleura covered by the tergal ex-tensions. The procoxal cavities are open behin
. Smithsonian miscellaneous collections. inated within the lateral wall of the tergum(B, Eps). The prosternum consists of two sclerites in the ventral wallof the segment between the bases of the first legs (fig. 21 A, S, Ss),the anterior one connected by the precoxal bridges (Acx) with thepleura. The prothoracic legs appear to be inserted between the ster-num and the lower edges of the tergum, but the lateral connections of NO. 2 THORACIC MECHANISM OF A GRASSHOPPER SNODGRASS 35 the legs are really with the inflected pleura covered by the tergal ex-tensions. The procoxal cavities are open behind, that is, there areno postcoxal sclerotizations. Lying before the coxa of each leg in thearticular membrane of the leg base is a small trochantinal sclerite(fig. 20 A, Tn). The protergum.—The tergum of the prothorax, besides coveringthe back and sides of its own segment, projects posteriorly over thedorsum of the mesothorax in a wide, triangular lobe which fits betweenthe bases of the folded front wings. The top of the tergal bonnet. Fig. 20.—The prothoracic tergum and pleuron of Dissosteira Carolina. A, outer view of left side. B, inner view of right side, showing episternuminvaginated within the tergum. a, posterior edge of anterior fold of tergum; b, anterior edge of posterior fold(B, Rd) of tergum; c, d, e, the external vertical grooves or sutures of the ter-gum (A) forming the internal tergal ridges (B) ; /, .9-, h, i, horizontal suturesand their ridges connecting the vertical sutures and ridges. (fig. 20 A, T) is cut by a deep transverse notch somewhat before themiddle, and the part before the notch is compressed into a medianridge. Each lateral area of the protergum is marked by a number of groovesforming a definite pattern, and by two non-impressed lines. The firstnon-impressed line (fig. 20 A, a) lies near the anterior border of thetergum and runs parallel with it; the second (b) extends downwardin a sinuous course just posterior to the dorsal tergal notch. These
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Keywords: ., bookauthorsm, bookcentury1800, bookdecade1860, booksubjectscience
