NESTING OF THE ROCK WREN CATHERPES 163 



various ; usually the nest is built in a rift of rocks, or on the 

 ground beneath some shelving rock. The variety of the 

 Eock Wren which inhabits the island of Guadaloup, off the 

 coast of Lower California, is said to ingeniously block up the 

 entrance to its nest with an artificial wall built of pebbles, leav- 

 ing an aperture only just large enough to pass. A nest has 

 been found in the natural cavity of a clay bank ; and others, 

 as already hinted, between the logs of a cabin. As to the 

 period of laying, we are again met by great diversity, in conse- 

 quence of the wide range of the bird during the breeding 

 season. Dr. Cooper's Fort Benton nest contained nine eggs, 

 in June ; at San Diego, the same naturalist found young birds 

 in May ; in New Mexico, Mr. Henshaw took a nest containing 

 three young and one egg, June 17 ; and another, with four 

 nearly fledged young, was secured July 28, though birds of the 

 year already flying had been observed two weeks previously. 

 This indicates, of course, that at least two broods are reared ; 

 and such is doubtless the rule, in the southerly localities at any 

 rate. The eggs seem to run from four to eight or nine to a 

 clutch ; tney measure from 0.72 to 0.77 in length by 0.60 to 

 0.66 in breadth, averaging about ^x | ;. they are noticeable for 

 their rotundity, and the crystalline purity and smoothness 

 of the shell. The white ground is rather sparingly sprinkled 

 with distinct reddish-brown dots, usually massed at the large 

 end or wreathed around it. 



Genus CATHERPES Baird 



Chars. — In general features, even to the system of colora- 

 tion, and the tints themselves, closely resembling Sal^pinotes, 

 Tail and wings much as in that genus. Bill singularly attenu- 

 ate, about as long as the head, nearly straight in all its out- 

 lines, even the gonys being scarcely appreciably, and the cul- 

 men and gonys only slightly, deflected toward the end. There 

 appears to be some peculiarity in the direction of the axis of 

 the bill as a whole in comparison with that of the rest of the 

 skull, there being little rise of the forehead from the line of the 

 cultoien. Tarsus short, not exceeding the middle toe and claw, 

 with a tendency to subdivision of the tarsal plates behind. 

 Hind toe and claw as long as the middle one. Lateral toes of 

 unequal lengths, the tip of the claw of the outer one reaching, 

 or rather surpassing, the base of the middle claw. 



As in the case of Salpinctes, this genus possesses but one 

 known species, which is separable into two geographical races. 



