1914] Crandall: Notes on Costa Rican Birds. 341 



fledged birds, while one contained the two eggs mentioned under 

 Cassidix. In only one case did a nest contain two young Gym- 

 nostinops, while a Cassidix shared another with the single right- 

 ful inmate. The third colony, also examined on May 5, was one 

 of nineteen nests. Only three were occupied, each containing a 

 nearly fledged young bird. It seems probable that other young 

 had flown, as some of the nests showed signs of recent occupancy. 



It will thus be seen that of twenty-one nests containing 

 young or eggs, in only one instance was there more than one 

 occupant. It seems evident, then, that the normal complement 

 of this species is but a single egg. 



The egg collected measures 42.4 x 25.1 mm., seeming to be 

 rather abnormal as to length (Fig. 117) . It is a very pale bluish 

 white, lightly spotted throughout, but heavily encircled at the 

 larger end with chocolate blotches. 



The newly hatched chicks are blackish, the skin leathery and 

 shiny, and quite devoid of down. The beak is black, with both 

 mandibles tipped with yellow, the gape being pale yellow. 



The stomach of one young bird examined was crammed 

 with insect remains and fruit seeds. Several very large locusts 

 were represented, the bird apparently not being inconvenienced 

 by the huge tibial spines. 



The food of the adults is evidently of a highly varied 

 character. Many kinds of fruits and berries enter into it, as 

 well as such animal food as they chance to come across. Birds 

 were observed carrying locusts, roaches and other insects to the 

 young, and on one occasion a freshly-killed mouse was found in 

 a nest. A dead frog given to a captive specimen was seized and 

 passed to and fro in the great beak. The frog was then held 

 down with one foot, Jay fashion, and each leg carefully broken, 

 when it was swallowed without further ado. 



The notes and display of the male Gymnostinops have been 

 described too often to be repeated here. It was noted, however, 

 that the male often flew against a nest with great force, so that 

 it swung about wildly, and that the curious gymnastic perform- 

 ances were executed while the bird hung sideways in this 

 perilous position. 



