106 Zoologica: N. Y. Zoological Society. [I; 3 



to save their eyelids — their one unprotected spot. Although the 

 cassiques cannot have learned from experience of the terrible 

 wounds which the wasps can inflict, yet they are keenly alive to 

 the advantages to be derived from close association with them. 



The wasps' nest is built far out on the tip of the limb of 

 some forest tree, and the long pendant homes of the cassiques 

 are placed close to it, sometimes eight or ten on the same branch, 

 and others on neighboring limbs, so near that the homes of in- 

 sects and birds rattle against each other when the wind blows. 



One such community was placed rather near the ground, 

 where we could watch the inhabitants closely. Frequently when 

 one or two of the big birds returned to their nests with a rush 

 and a headlong plunge into the entrance, the whole branch shook 

 violently. Yet the wasps showed no excitement or alarm ; their 

 subdued buzzing did not rise in tone. But when I reached up 

 and moved the branch gently downward, the angry hum which 

 came forth sent me into the underbrush in haste. From a safe 

 distance I could see the wasps circling about in quick spurts 

 which meant trouble to any intruder, while the excited cassiques 

 squeaked and screamed their loudest. Whether the slight motion 

 I gave to the branch was unusual enough to arouse the insects, 

 or whether they took their cue from the cries and actions of the 

 alarmed birds, I cannot say. 



The nests are beautifully woven of very tough palm-leaf 

 shreds and grass stems, in shape like tall vases, bulging at the 

 bottom to give room for the eggs and young birds, and with an 

 entrance at the side near the top. We found still another in- 

 stance of the unusual ability of these birds to adapt themselves 

 to changing conditions. Those nests which were already de- 

 serted or with young ready to fly had simple rounded tops arch- 

 ing over to protect the entrance from the sun ; but in the nests 

 which were in process of construction, now at the beginning of 

 the rainy season in early April, there appeared an additional 

 chamber with a dense roof of thatch, in which one of the 

 parents, the male in at least one case, passed the nights, safe 

 from the torrents of sudden rain. 



These cassiques seemed rather omnivorous, feeding on 

 grubs, insects of all kinds, small fruits and berries. 



The courtship display of the male, was to lower the head 

 and neck, spread the tail, raise the yellow shoulders and fluff up 

 the yellow feathers of the back and rump, thus bringing almost 

 every bit of color into view at once. 



The usual number of eggs seemed to be two. A typical nest 

 collected from the colony at La Brea on April 11th contained 



