342 PROCEEDINGS OF THE ACADEMY OF [May, 



ruary 7, 1907; March 15 and 16, 1907 and 1908; April 7, 10, and 18, 

 1907. Five males, two females. 



San Ignacio, Prov. of Mendoza. Elev, 1,325 meters. January 

 15, 1909; March 15 and 22, 1908; April 5, 1908; December 13, 1908. 

 Eleven males, nine females. 



Potrerillos, Prov. of Mendoza. Elev. 1,368 meters. February 

 23, 1908. One male. 



Buenos Aires. May 3, 1907. One female. 



This very interesting series of one hundred and eleven specimens 

 shows that considerable variation in size and color is present in the 

 species. Apparently the size variation is more geographic and 

 enviromnental than individual. The San Juan and Caucete series 

 are very similar in proportions and size, such individual variation In 

 the latter as is noticed being found in both lots. The La Paz, Pedre- 

 gal, Mendoza, and large portion of the Chacras de Coria and San 

 Ignacio series are uniformly smaller, with shorter tegmina and 

 consequent more robust appearance. Two males and two females 

 from San Ignacio and several males from Chacras de Coria are similar 

 in general form to the San Juan and Caucete lots. A single male 

 from Mendoza is of similar proportions, but the size is no greater 

 than the other Mendoza specimens. Apparently at these three 

 localities the differences are environmental, as they are decided and 

 correlated with color characters. Such differences produced by 

 isimilar agencies are frequently found in species of the allied North 

 American genus Melanoplus. 



The first color type, which almost invariably has longer tegmina 

 than the second, is always paler, the base color varying from buff to 

 nearly ochraceous, with the median portion of the dorsum more or 

 less suffused with tawny to chestnut. The postocular bars are always 

 decidedly indicated and the base color of the femora and tibiae in 

 the two forms varies with the general base color. The second type 

 has the base color nearer gamboge and saffron yellow, but little 

 evident, however, as the overlying suffusion of from clove brown to 

 clay color is, as a rule, heavier and more extensive than in the first 

 type, permitting less contrast between the region of the postocular 

 bars and other areas. The females of this latter type are much 

 duller than the male. The dark suffusion of the sharply delimited 

 dorsal two-thirds or so of the external face of the caudal femora 

 varies greatly in intensity, usually more solid and darker in the 

 individuals of the second type. 



Representative individuals of both sexes taken at random from 

 the larger series measure as follows: 



