COMPARATIVE OOLOGY OF NORTH AMERICAN BIRDS. 



481 



our Goatsuckers differ quite materially from those of l>r. Goues, which 

 is probably due to the fact that the eggs of the several species them 

 selves differ to such a marked degree both in color, form, and markings. 



According to Newton, "The Guacharo (Steatomis) is said to build 

 a howl like nest of clay, in which it lays 2 to 1 white eggs, with a 

 smooth but lusterless surface, resembling those of some Owls." (Art. 

 "Guacharo," Encycl. Brit. 9th ed. Vol. \\i. p. 227.) And we may add, 

 this is not the only character we know of (hat indicates caprimulgo- 

 strigine affinity. 



The Humming-birds need not detain us long; and it is very remarka- 

 ble that for so large a, group there is such complete uniformity, so far 

 as we are at present aware, in their oology. Tersely it may be said 

 that the Trochili all lay tiro pure white eggs, large for the bird in any 

 species, and generally of an elliptical-oval, or elliptical-ovate form. 

 These eggs remind me somewhat of the eggs of our smaller existing 

 lizards. 



In another suborder, the Cypseli we are still ignorant of the charac- 

 ter of the eggs of several of the species, but those of Chcetura pelagica 

 are well known. In that species from 4 to 5 are usually in a set. 

 They are pure white, and narrowly elliptical in shape. The eggs of 

 Cypscloide* niger have as yet not been collected by any naturalist that 

 I am aware. The eggs, too, of Micropus melanoleucm are unknown to 

 me. 



Lastly we come to that great host of birds included in the Passeees, 

 and here I propose to contrast the descriptions of Cones and Ridgway, 

 confining myself principally to the various genera, occasionally only 

 to the family where the eggs of the birds in the latter are very similar. 

 Where birds of the same group differ to any marked degree such dif- 

 ferences will be noted. Where the eggs of others are unknown the 

 fact will also be shown; and I trust that such a table, condensed and 

 compared, although it may add nothing that is new to the subject, 

 will yet prove to be useful to the working oologist. 



Oology of North American Paaseres. 



Families, genera, etc. 



< ' >s. 



Ridgway. 



1. TYRANMIi.K. 



Milvulus forfieatus . . . 



'I'u i <i a nun tyrannus . . 



Pitangus derbianus . . . 



Eggs 4-5; white, boldly blotched 

 with reddish on the surface, and 

 lilac shell-spots. 



Eggs usually 4 f>. white, rosy, or 

 creamy, variously spotted or 

 blotched in bold pattern with 

 reddish and darker brown sur- 

 face spots and lilac shell-mark- 

 ings. 



Not given 



II. Mis. 114, pt. 



-31 



Eggs 3-5; .88. XG6: pure white 

 or creamy white, boldly but spar- 

 ingly spotted witli rich madder- 

 brown and lilac-gray. 



Eggs3 5; white, spotted with rich 

 madder-brown or chestnut, and 

 lilac-gray. [ Eggs of this genus 

 are particularly handsome ob- 

 jects.—!;, w. s'.| 



Eggs 3-5, huffy white, speckled 

 ami spotted (the markings mostly 

 longitudinal), chiefly on larger 

 end, with madder-brown and 

 purplish gray. 



