206 Psyche iDecember 



THE MALE OF ECITON VAGANS OLIVIER. 



By William Morton Wheeler, 

 Bussey Institution, Harvard University. 



Only the worker form of Eciton vagans is known, although it 

 was first described by Olivier as long ago as 1791 and is one of the 

 most abundant and conspicuous legionary ants of tropical America 

 from Mexico to Southern Brazil. That its female has never been 

 seen is not surprising, because female Ecitons are among the 

 rarest of insects, but it is strange that the male of such a common 

 insect should not have been described as one of the numerous 

 species of Labidiis, a genus to which all male Ecitons were referred 

 by Latreille, Westwood and other entomologists of the first half 

 of the nineteenth century. The only described male, however, 

 that may prove to belong to E. vagans, is E. dubitatum Emery 

 (vide infra), but this is by no means certain. 



November 29, 1911, while collecting ants at La Sabana, a suburb 

 of San Jose, Costa Rica, I came upon a small army of E. vagans 

 rapidly ascending the grassy slope of a ravine. While I was 

 watching the rust-red workers a large chocolate brown male with 

 infuscated wings came marching along in the file, and a few mo- 

 ments later another appeared alternately flitting and walking in 

 the grass about a foot away from its worker companions but 

 moving in the same direction. There could be no doubt that 

 these two insects were accompanying the army and that they 

 belonged to the same species as the workers, because the most 

 careful search revealed no other Ecitons on the whole grassy 

 slope of several acres. Moreover, it was not the regular season 

 for forays of these ants, for I encountered very few species of the 

 genus in Panama, Costa Rica and Guatemala during November, 

 December and January. Only E. cwcum Latr., which is a subter- 

 ranean species, seems not to interrupt its forays during these 

 months, I append a description of the two males which I captured. 



