ANATOMY OF MARELLIA REMIPES — CARBONELL 65 



the structures that appear to him to be different from those of the pre- 

 viously described species. 



Acknowledgments. — The present work is the result of research 

 performed by the author in the Universidad de la Repiiblica, Monte- 

 video, Uruguay. It was done almost entirely in the Insectary Section 

 of the Facultad de Agronomia and was based on specimens belonging 

 to the Laboratory of Entomology of the Facultad de Humanidades y 

 Ciencias and collected on field trips organized by the Laboratories of 

 Vertebrate Zoology and Entomology of this College. 



The writer acknowledges his deep gratitude to Dr. R. E. Snodgrass 

 for the much needed correction of the style of the manuscript. He 

 also wishes to thank Dr. B, P. Uvarov, who made available his bibli- 

 ography on the subject and made useful suggestions on the work to be 

 done. 



I. GENERAL FORM OF THE BODY 



Marellia remipes (fig. i) is a stout-bodied grasshopper of medium 

 size. Its antennae are relatively short, and its hind legs are strong 

 and well developed. The males are of a somewhat more slender build 

 than the females, and their dimensions are slightly smaller. 



The body of these insects is depressed and, the upper part of it 

 being considerably narrower than the sternal region, its lateral walls 

 slope downward and outward from the dorsum to the broader venter. 

 A transversal section through the thorax of the insect appears shaped 

 like a trapezoid, with its broader base down, this base being noticeably 

 larger than the height of the figure. 



In the phytophilous grasshoppers, the body is usually compressed 

 instead of depressed. Though the sternal region is often in them, too, 

 broader than the tergal one, this condition is never so marked as in 

 Marellia. In this respect, the general aspect of Marellia resembles 

 that of the geophilous South American Ommexechidac, in which the 

 depressed shape of the body and the exaggerated width of the sternal 

 region, particularly in the pterothorax, are even more marked. 



Among the populations of Marellia rcmipcs studied by the writer 

 in northern Uruguay, brachypterous (fig. i B) and macropterous 

 (fig. I A) forms were found together, the former being about twice 

 as abundant as the latter (Carbonell, 1957). 



II. THE HEAD AND THE MOUTH PARTS 



The head of Marellia remipes is shown in figure 2. It agrees in 

 general with the descriptions given of the head of other grasshoppers, 

 but shows, too, some peculiarities of its own. It is somewhat conical 



