82 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 37 



first tarsomere shows the usual three cushionHke tarsal pulvilli (figs. 

 13C, 14C, TP). 



The second tarsomere (fig. 14 A, 2Tar) is as usual the smallest 

 of the three, and the least modified. The third (jTar) is large and 

 compressed, showing a peculiar expansion of its upper margin. In 

 its position it follows the torsion shown by the first, being in an almost 

 vertical, slightly inclined plane, so that its external surface can be 

 seen from above (see fig. 13 A). The pretarsus is similar to the 

 pretarsi of the front and middle legs and shows likewise a poorly 

 developed arolium. 



VI. THE ABDOMEN 



The abdomen of Marellia rcmipes is conical in shape (fig. 15), its 

 apical portion being distinctly pointed. As we shall see later, the 

 terminal structure of the abdomen in Marellia is markedly different 

 from that of most grasshoppers, particularly in the females. 



The whole abdomen is somewhat depressed in shape; the sternal 

 region is broad and flat, and the terga show a distinct median dorsal 

 carina from which the sides of this region slope down and out to 

 meet the sterna. A transversal section of the abdomen is shaped like 

 a triangle with a flat, broad base and convex sides. In the ovigerous 

 female the contours of the abdomen become rounded. In the male the 

 abdomen is more slender than in the female, and its subterminal part 

 is slightly enlarged transversally. 



In its pregenital or visceral part, the abdomen of Mare Jim does not 

 show major differences from the corresponding region of Dissosteira 

 (Snodgrass, 1935a), Dociosfaurus (Jannone, 1939), or Nomadacris 

 (Albrecht, 1956). It shows, however, differences of detail, especially 

 in regard to the number and disposition of the spiracles. 



The first abdominal spiracle (fig. 15, ISp) is remarkably large, 

 much larger than the following ones. Celow this spiracle, on the edge 

 of the first abdominal tergum, there is a region covered wdth hairs 

 which continues over the membranous zone below the tympanum and 

 the posterior part of the edge of the first tergum to the whole inferior 

 edge of the second tergum where the second abdominal spiracle 

 (lisp) is located. The first abdominal spiracle is covered by the pro- 

 nounced lobe of the costal region of the fore wing already described. 

 This circumstance, its large size, and the presence of what looks like 

 a zone of hydro fugous hairs in its vicinity, suggest that this spiracle 

 may play an important role in the respiration of the insect when sub- 

 merged. The second abdominal spiracle (IISp), surrounded by dense 

 pilosity and protected by the ample base of the hind femur, may also 



