CLASSIFICATION AND SYNONYMY. 



The changa is a member of the insect order Orthoptera, which con- 

 tains the roaches, walking sticks, mantids, grasshoppers, locusts, 

 and crickets, and is said to number at least 10,000 known species. 1 

 According to recent systems of classification 2 the mole crickets, 

 with their fossorial forefeet, form the family Gryllotalpidse, but 

 they were formerly considered as a subfamily of the cricket family 

 Gryllida3. The changa is the only mole cricket known to occur in 

 Porto Rico. 



The species was first described by Scudder in 1869 (41). Gund- 

 lach and Stahl both mention the insect as Gryllotalpa hexadactyla, 

 which is a quite different species and is not known to occur in Porto 

 Rico. Saussure in 1870 considered this species to be merely a 

 variety of S. didactylus. Rehn and Hebard have recently pub- 

 lished" the opinion that " the species found abundantly in the south- 

 eastern United States, the West Indies, and portions of South 

 America, and which has been frequently recorded as S. didactylus, 

 represents instead vicinus of Scudder. This species is very closely 

 related to didactylus of Latreille (described from Surinam and 

 found elsewhere in South America and northward to Costa Rica), 

 but is somewhat heavier." As given by Scudder in his table for 

 the separation of species of Scapteriscus (41, p. 7), S. vicinus differs 

 from S. didactylus in that the tibial dactyls almost or quite touch 

 at the base, whereas in /S. didactylus they are distant from each 

 other at the base by at least one-half the width of the dactyls. Rehn 

 and Hebard consider S. agassizii of Scudder synonymous with 

 S. vicinus.* 



HISTORY AND DISTRIBUTION. 



In economic literature this injurious mole cricket has always been 

 treated under the specific name didactylus, a name, as above stated, 

 now applied to a closely related species. The first mention of the 

 insect as a pest appeared in 1836 in letters from A. M'Barnet, of St. 

 Vincent (32), who described the cricket as injurious to pastures and 

 to cane plantings. Although the pest is named only as the "mole 



1 Sharp, D. Insects, I. Cambridge Natural History, vol. 5, p. 201. London, 1895. 



'Brues, C. T., and Melander, A. L. Key to the Families of North American Insects, 

 p. 14. Boston and Pullman, Wash., 1915. 



8 Since the above was written Mr. James A. G. Rehn, in a letter dated Apr. 7, 1917, 

 has defined the range of Scapteriscus vicinus and /S. didactylus as follows : " The limits 

 of its [8. vicinus] range appear to be, as far south as Las Palmas, Chaco, Argentina, 

 and Santa Cruz de la Sierra and Puerto Suarez, Bolivia ; west to the Rio Pacaya, Peru ; 

 east to Piauhy, Brazil; and north to Colombia and Venezuela and through the West 

 Indies, occurring also in eastern Georgia. The range of true didactylus appears to be 

 limited to a relatively circumscribed area in northeastern South America from eastern 

 Venezuela through the Guianas to lower Amazonian Brazil. This information on didac- 

 tylus has not been published as yet, but is clearly evident from material in our collec- 

 tions." 



