no FIELD MUSEUM OF NATURAL HISTORY ORNITHOLOGY, VOL. I. 



at Mazatenango, two at Patulul, and one at San Jose. These speci- 

 mens present so much variation in color that the entire series of the 

 species formosa in this Museum has been brought in for comparison. 

 Aside from the Guatemalan specimens, there are six from Apipiluluca, 

 Guerrero, and one from San Geronomo, Oaxaca, Mexico; one from 

 Salvador; two from San Raphael del Norte, Jinotega, nine from 

 San Geronomo, Chinandega, and one from San Emilis, Lake Nicara- 

 gua, Nicaragua; and one frofn Orosi, northwestern Costa Rica. The 

 half dozen from Guerrero have more or less black on the occiput, 

 black malar patches, and bluish gray backs. These are C. f. formosa. 

 The Oaxaca specimen and those from Guatemala, Salvador, Nicaragua 

 and Costa Rica have no black on either occiput or malar region, and 

 are thus clearly differentiated from C. f. formosa by these characters. 

 They are not, however, all distinguishable from C. f. formosa by the 

 color of their backs. Only those from the Pacific side of western 

 Guatemala have their upper parts so dark blue as to be conspicuously 

 different from it in this respect. This dark blue form is typical of 

 Mr. Nelson's C. f. azurea. The specimens from San Raphael del 

 Norte, Nicaragua, are as gray above, as those from Guerrero taken 

 in the same month, that is to say, as gray as C. f. formosa. The 

 specimens from Gualan, El Rancho, Salvador, and Oaxaca are all 

 nearer gray than blue above, while those from Orosi and Chinandega 

 are intermediate between the extremes of blue and gray of this blue- 

 crowned, immaculate-cheeked aggregate, which is conveniently in- 

 cluded under the name azurea. While there is no difficulty in dis- 

 tinguishing the pale interior form from the darker blue azurea, which 

 occurs in its typical state only along the Pacific slope of Chiapas and 

 western Guatemala, specimens from the Pacific coast region from 

 southern Guatemala to northern Costa Rica are intermediates between 

 the two types, and the systematic ornithologist would probably find 

 the worry of disposing of these, so great as to outweigh the satisfac- 

 tion of recognizing a color variant by name. 



The map relating to the distribution of the races of Calocitta 

 formosa is based mainly upon specimens in this Museum. Material 

 to fix the eastward extension of C. f. formosa is not available. Azurea 

 is represented by the letter A, the type locality being indicated by a 

 circle. The letter X shows three points from which have come 

 specimens of the pale form, which has unspotted malar areas. These 

 latter localities are all east of the mountain chain that parallels the 

 Pacific coast, and at least two of them, that is to say, the interior 

 of Guatemala and eastern Oaxaca, have a semi-arid, cactus-bearing 



