154 ENTOMOLOGICAL NEWS [April, '09 



Migrations of Athena chiron Fabricius 

 BY FREDERICK KNAB, Washington, D. C. 



Throughout the greater part of tropical and subtropical 

 America Athena chiron is, at certain seasons, one of the most 

 abundant butterflies. It may often be seen congregated in 

 large numbers at puddles or wet spots of ground to sip moist- 

 ure. During our stay at Cordoba, Mexico, Dr. Fenyes and the 

 writer witnessed an extensive migration of this species. Our 

 observations extended over four days, May 15-18, 1908, and 

 were brought to a close by the departure of the writer. It is 

 to be supposed that the migration continued for some time 

 after, while the conditions prevailed which favored it. The 

 butterflies did not form a swarm but were traveling independ- 

 ently. Numbers of them could be seen scattered over the 

 countryside, many of them flying in a northeasterly direction, 

 while others hovered about bushes and herbage or about moist 

 places. In town they could be seen rapidly passing over, just 

 above the roofs of the houses. There were some almost con- 

 stantly in sight from our station in the courtyard of our hotel. 

 The flights ceased during periods of cloudiness, only to be re- 

 sumed when the sun again appeared. 



The appearance of these butterflies at Cordoba in such large 

 numbers was due to their sudden development in the adjoining 

 hot, low regions as a result of the first rains of the warm sea- 

 son. The steady currents of heated air, passing up the moun- 

 tain sides from the valley of the Rio Blanco, carried these but- 

 terflies along with them. It would therefore seem that the 

 migration was due to natural causes rather than to any pur- 

 pose or migratory instinct on the part of the insect. 



Godman and Salvin observe'd a migration of a like charac- 

 ter, and under similar conditions, in this same species of but- 

 terfly, near San Geronimo, in Guatemala. As their account, in 

 the Biologia-Centrali Americana (Lepid, Rhopal., vol. I, p. 

 289) is accessible to but few readers, I quote it here : 



"We were riding one afternoon down the mountain side 

 skirting the plain of Salama, when we met thousands of this 

 species, which were flying with the wind along the hillside. 

 All were going in the same direction, which took them to the 

 higher ranges of this district, and beyond into the valleys of 

 the Polochic and Motagna/' 



