430 Annals of the Carnegie Museum. 



well as typical examples of earh form occurring well within the area of 

 predominance of the other. The question is complicated by the 

 consideration that we are dealing here, not with a continuous land 

 area of distribution, but with a group of islands, which condition 

 constitutes a visible (though not insuperable) barrier to the extension 

 of the range of a sedentary species such as the present one is believed 

 to be. Thus, while the occurrence of individuals of typical crassirostris 

 on Great Inagua in the breeding season could scarcely be accounted 

 for on the assumption that they were migrants from the northern 

 islands, it would be equally difhcult to call in a like theory to explain 

 the presence of flavescens on New Providence during the winter 

 months. It is customary to account for the exceptional or occasional 

 occurrence of birds outside their generally recognized geographical 

 limits by saying that such individuals are "migrants" or "strays," 

 but I fail to see how such an explanation could well apph' in this case. 

 In short, Vireo crassirostris flavescens is not, strictly speaking, a 

 geographical race or subspecies, since its distribution does not coincide 

 with any definite area as distinguished from that occujiied by T'. c. 

 crassirostris. We might suppose that this is a case of as yet imperfect 

 subspecific segregation through individual variation, the bright- 

 colored birds having become the more completely localized. But 

 that these two supposed forms can be considered as anything more than 

 color-phases of a single species is exceedingly doubtful when we 

 remember that a precisely parallel variation obtains in at least two 

 closely allied continental species of this genus, Vireo ochracciis and 

 Vireo carmioli. It would be interesting to know whether the pale 

 and bright birds breed together and what is the immediate result, or 

 whether their local habitats are different. This is a question for the 

 field naturalist to settle. 



I have examined ]\Ir. Cory's series of Vireo allcui from Grand 

 Cayman and Cayman Brae, eighteen specimens in all. Many of these 

 are discolored by the preservative used, and all are in wretched 

 plumage with the sole exception of the type, which lacks the tail. 

 After comparing these specimens carefully with Bahaman birds I 

 cannot verify any of the distinctive characters alleged to exist, but 

 until better and comparable material is available I should hesitate to 

 pronounce the two identical, as in such case the area of distribution 

 would be divided by the island of Cuba, which is occupied by another 

 form, Vireo Piivdlachii. 



