272 A YEAR OF COSTA RICAN NATURAL HISTORY 



wise a population of hanging "yellow tails'" nests and the 

 call of the birds could be heard for a considerable distance. 

 The number of nests was much smaller than on the tree at 

 La Junta. 



Not long after entering the forest, I had my first view of a 

 living example of the largest species of dragonfly now known 

 to exist — Megaloprepus ccerulatus — found in the lower parts 

 of tropical America from Mexico to Bolivia. Its very 

 slender body attains, in the largest individuals, a length of 

 five inches and it has a wing-spread of more than seven 

 inches. It owes its specific name, ccerulatus, to the fact that 

 on its large otherwise clear wings is a broad, dark, purple- 

 blue band which makes the insect conspicuous when flying 

 through the forest. Some writers (who have not seen this 

 insect in life) have suggested that the dark bands on the 

 wings, by resembling flickering shadows cast by leaves, etc., 

 are thereby protective, but I could not see that the supposed 

 resemblance exists. This day I saw two or three individ- 

 uals flying from dense vegetation into the trail. When fly- 

 ing all four wings were spread far apart from each other, 

 the body was horizontal. The flight was sufficiently slow 

 to allow the movement of each wing to be seen; but in spite 

 of this slowness the insect can dodge. Mr. Barnes com- 

 pared the motions of the wings to those of a windmill, but I 

 should say that the eff^ect produced by the moving wings 

 was more like that of a jumping-jack with movable arms 

 and legs pulled by one string, rather slowly but at regular 

 intervals. When caught and held by the wings, the legs 

 were folded against the thorax and remained immobile, 

 even when they were touched or rubbed — the insect seemed 

 to "play 'possum." When held by the mid-abdomen, move- 

 ments in legs and wings soon appeared. When I struck 

 at individuals in the forest with my net and missed them 

 they usually rose in the air, at the same time making into 



