88 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. lOG 



to the subfamilies and the genera. Euschdngaiitia is in the sub- 

 family Trombiculinae. 



The historical development of the genus Euschongastia Ewing, 

 1938, has been confused only by differences of opinion or inter- 

 pretation which have occurred during the recent growth in the 

 systematics of chiggers. As groups of species were shifted into 

 new genera in an effort to get more natural combinations, 

 acarologists did not always view the problem in the same way 

 and did not shift their nomenclature simultaneously and iden- 

 tically. 



The oldest species included in Euscho^igastia, as it is defined at 

 present, is E. trouessarti, described by Oudemans in 1910 and 

 placed in his new genus Schongastia, type species Thromhidium 

 vandersandei Oudemans, 1905. Only three species were included. 

 Later, many species were added by several v/orkers. Ewing 

 (1929d) separated several species from Schongastia and placed 

 them in a new genus, Neo schongastia, type species Schongastia 

 americana Hirst, 1921. E. trouessarti was included in the new 

 genus in 1932. 



In 1938 Ewing erected the monotypic genus Euschongastia for 

 his new species E. americana. His diagnosis in effect split 

 Neoschongastia. 



In 1939 Womersley proposed a new genus, Paraschongastia 

 (type species Neoschongastia yeomansi Gunther, 1939, by sub- 

 sequent designation in Womersley and Heaslip, 1943) , for a group 

 of four species within Neoschongastia. 



Vitzthum (1942) considered Euschongastia as a subgenus of 

 Schongastia, but subsequent authors have retained it as a full 

 genus. 



Ewing (1946b) showed that the four species placed in Para- 

 schongastia by Womersley were congeneric with the type species 

 of Neoschongastia. Therefore, Paraschongastia Womersley, 1939, 

 was a synonym of Neoschongastia Ewing, 1929. Ewing then 

 restricted Neoschongastia to this newly formed group. This 

 action excluded many species formerly in Neoschongastia. To 

 accommodate these excluded species, he erected a new genus, 

 Ascoschongastia Ewing, 1946, type species Neoschongastia 

 nialayensis Gater, 1932. Workers outside the United States have 

 followed Ewing's diagnoses of these genera. 



However, Wharton (1948) has pointed out that the type species 

 of Ascoschongastia had an unusual morphological feature — the 

 posterolateral setae lying off the scutum — which made it almost 



