58 A YEAR OF COSTA RICAN NATURAL HISTORY 



extensive distribution. P. flavescens is well known as the 

 most widespread of all dragonflies of the world, having been 

 found in all quarters of the globe except Europe, in many an 

 oceanic island, in a Himalayan pass at an elevation of 11,000 

 feet and was observed to fly in numbers at 1 1 P. M. of the 

 nth of April, 1896, on to a Peninsular and Oriental steamer 

 in the Indian Ocean, 290 miles from the nearest land. P. 

 hymenaa is confined to the New World, but ranges from New 

 Jersey and South Dakota to Chile and Argentina. It is, 

 therefore, not surprising to find these Pantalas in Costa Rica. 

 The third species is much more remarkable. It is the 

 smallest of all the species known in the United States and 

 bears the disproportionately long name of Anomalagrion 

 hastatum. It is, in one respect, unique among all dragonflies 

 in that the stigma, or opaque spot, is, on the front (but 

 not the hind) wing of the male, set back from the front 

 edge of the wing instead of being bordered by that edge, — 

 whence Anomalagrion. The body of A. hastatum is very 

 slender and its delicate wings do not permit of anything but 

 a weak flight. Yet it has been found throughout the United 

 States east of the Rocky Mountains, in Mexico, Central 

 America, the West Indies, Venezuela and even in the Gala- 

 pagos Islands, although, previous to our collecting it, it had 

 not been reported from Costa Rica. Within the last-named 

 country we found it at altitudes between 5000 (El Alto) 

 and 2200 (Turriicares) feet, and on both the Atlantic and 

 Pacific slopes. As it has been found at sea-level in Guatemala 

 and Honduras, it is likely that it occurs at the similar loca- 

 tion in Costa Rica. One of the unsolved problems of geo- 

 graphical zoology is why this feebly-flying insect should 

 have so extensive a distribution when other species of more 

 powerful flight and living in similar situations, both as 

 larvae and adults, are confined to much smaller areas. In 

 its larval stages, Anomalagrion must possess a great range of 



