Vol. XIII 



Cherrie, A New Ckordeiles from Costa Rica. TTC 



Two downy young taken by Mr. John Schaler from the same 

 nest at Rock Lake, on July 17, have an interrupted black bar 

 across the breast, black at the base of the mandible, and the entire 

 upper parts mottled with black, but while the ground color of one 

 is pure white, that of the other is pale ochraceous-buff, becoming 

 white only in the center of the abdomen. This difference may 

 be one of sex, or, taken in connection with the ochraceous females 

 mentioned, connect sennetti with henryi. 



Wherever we went about the prairies we found this bird a rather 

 common summer resident, especially in the neighborhood of water. 

 It arrives the last week in May, and begins laying about the 

 twentieth of June. The pale colors of the male protect him 

 admirably, harmonizing with the dull gray of the fences and rocks, 

 perched on which he passes the day, while the darker colors of the 

 female render her less conspicuous when seated over her eggs on 

 the black soil. Six eggs in my collection from Towner County 

 average 1.67 in. in length by .88 in. in breadth, and are perhaps 

 a trifle paler with somewhat smaller markings than eggs of vir- 

 ginianus. 



Average measurement (with extremes) of thirteen specimens 

 (10 3,3 9): length, 9.53 (9.25-9.81); wing, 7.61 (7.08-7.87); 

 tail, 4.68 (4.53-4.79). 



AN APPARENTLY NEW CHORDEILES FROM COSTA 



RICA. 



BY GEO. K. CHERRIE. 



It is with much hesitation that I present the following as char- 

 acterizing a new Nighthawk of the C. virginiatius group, — that 

 is, the species or subspecies in which the white wing-patch is 

 posterior to the tips of the secondaries. 



