1909] Beebe: Birds of Northeastern Venezuela. 107 



two eggs. It measures seventeen inches in length, with the en- 

 trance three inches in diameter. The neck narrows to two 

 inches and the nest chamber at the bottom widens out to three 

 again. The extra chamber at the top of the nest, is above and 

 to the right of the entrance, about three inches high and deep, 

 by five inches across. The nest lining is of very fine grasses. 



The eggs are white, spotted, especially at the large end, with 

 many small superficial dots, of various shades of brown, and a 

 few large deeper stains of pale lavender. They measure 30 x 20 

 and 31 x 20 mm. 



The communal condition of life existing between birds and 

 wasps is probably of more general occurrence than we suppose. 

 So persistent a habit of the yellow-backed cassique is this asso- 

 ciation with wasps, that it has been observed in many other places 

 throughout Venezuela by Mr. Cherrie, and a group illustrating 

 this communalism has been placed on exhibition in the Brooklyn 

 Museum. The value to the wasp, if any, is unknown, but to the 

 bird the association is of the greatest importance. In 1904 I 

 described and illustrated a similar communal relationship in 

 Western Mexico between the Sinaloa wren, Thryophilus sinaloa, 

 and a wasp which built a single open comb nest.* In Savanilla, 

 on the present trip, we observed in four instances, nests of two 

 species, a thrasher and a wren, built within a foot of small, glob- 

 ular wasps' nests. 



Mr. J. J. Quelch, in writing of this same species of cassique** 

 says "It is a curious fact that almost invariably these nests are 

 found built in the immediate vicinity of the nests of stinging 

 ants and wasps which render them safe from molestation, though 

 the insect homes are often so hidden that it is difficult to per- 

 ceive them until the attempt to secure the birds' eggs has been 

 made." 



A similar intimate association with wasps has been reported 

 of a South American flycatcher, of the Jamaican grassquit, 

 Euetheia olivacea olivacea, and of the yellow oriole. Icterus 

 xanthornus. 



Icterus icterus (Linn.) Troupial. 



A pair of these birds spent several hours near our house at 

 Guanoco on April 4th. They were of the rich orange type of 

 color. One was secured and found to have been feeding on 

 grubs. No others were seen during our stay. 



*"Two Bird-Lovers in Mexico," pp. 101-102. 

 **"Animal Life in British Guiana," p. 133. 



