232 A YEAR OF COSTA RICAN NATURAL HISTORY 



they carried these jaws wide open, at i8o°, so that the tips 

 were nearly a quarter inch apart and when they closed them, 

 as they did in a mechanical sort of way with a sudden snap, 

 there was a distinctly audible click. I do not doubt that 

 these ants can inflict a painful bite, although I did not 

 experience it. 



I cut across each leaf near its base, beginning at the out- 

 side of the clump and working in toward the center, so that 

 I could see whatever might be lodged between the bases of 

 the leaves. When the mass of plants first fell, considerable 

 water ran out from between the leaves, derived of course 

 from the rains. In all the bromeliads examined this day 

 there was also much mud between the leaves, especially the 

 outer ones, as well as dead leaves which had fallen from above 

 or perhaps been carried in by winds. 



The second bromeliad examined was lying on the ground 

 at the bottom of the Reventazon valley, still attached to its 

 host tree with which it had fallen. The third was near the 

 second on an upright tree, but although I got the rope over 

 it I was unable to dislodge it, pulling with all my strength, 

 and as I shook down a great many of the Odontomachi I 

 had some doubts whether this plant would have yielded 

 many other insects. The fourth and last was in the forest 

 about 200 feet above the river, perched on a tree-trunk ten 

 to twelve feet above ground. The unavoidable shaking, pro- 

 duced by my repeated attempts to throw the rope over it in 

 just the right spot, brought down a few small ants {Aptero- 

 stigma) but none of the larger Odontomachus, which I 

 took to be a favorable indication. After half an hour's 

 tugging and pulling the mass, consisting of three plants and 

 weighing surely not less than fifty pounds, fell to the ground. 

 I cut off the leaves as before and soon found a dragonfly 

 larva between two leaf-bases not far from the circumference. 

 In an hour's further searching no other such larvae were 



