340 Zoologica : N. Y. Zoological Society. [I ; 18 



breeding at many points about Guapiles, affording an excellent 

 opportunity for observation. 



The tree most commonly used by the Caciques is known 

 locally as the Ceiba. The trunk is smooth, with very thin bark, 

 which affords no hold for tree-climbing animals, and rises to 

 a great height before any branches spring out. The base is 

 reinforced by wide-spreading buttresses. The trees selected 

 are usually isolated and the majority are in open potreros or 

 in similar locations, although occasionally they are in open 

 forest. It was noted, however, that the branches are never in 

 contact with those of neighboring trees. 



The nests (Fig. 115) vary in number, from half a dozen to 

 as many as 100. Not more than one-third of the nests in any col- 

 ony examined were in use, and the occupied nests could be dis- 

 tinguished by their fresher appearance. It seems to be evident 

 that nests once used are seldom if ever repaired, the birds 

 usually building new nests, clustered in another part of the tree. 



In only two cases among the many colonies observed, was 

 there evidence of association with wasps, the birds seeming to 

 depend for protection on the great height of the trees. 



The nests are in the form of pendulous sacks, the opening 

 being at the top, which is not domed as in Cacious persicus. The 

 length of the many examples measured varied from thirty to 

 forty-eight inches, the average being about thirty-six inches. 

 The diameter of the more globular lower portions averaged nine 

 inches. In all cases, they were built chiefly of the aerial rootlets 

 of various tree parasites, mixed with coarser, weed-like mate- 

 rial and here and there a spray of Spanish Moss. The weaving 

 is rather coarse, and the nest in general is not nearly so fine as 

 that of Zarhyyichus wagleri. The nests contain a mass of 

 broken dried leaves, to a depth of two or three inches, which 

 form a cushion at the bottom. 



In all, the nests of three separate colonies of Gymnostinops 

 were examined. The first, on April 29, consisted of nine nests 

 of which but three were in use. Each contained a single young- 

 ster about one-half grown. In the second, on May 5, there were 

 forty-nine nests, of which fifteen were occupied. Fourteen con- 

 tained young in all stages from newly hatched chicks to nearly 



