516 Annals of the Carnegie Museum. 



ways! 4 Excepting in the generic synonymy above referred to, no 

 effort has been made in the present paper to sort the references 

 according to the use or non-use of the diphthong "ae" in the name, 

 except sometimes in cases where only a single reference is involved. 



Species and subspecies. — Twenty-two forms, referable to five specific 

 types, are recognized in the present review. All of the species are 

 subject to a great deal of sexual, individual, and age variation, and 

 C. passerine in particular is unusually plastic and susceptible to 

 varying conditions of environment. The difficulty of discriminating 

 these geographical variants arises not so much from the subtle nature 

 of the differential characters as from the necessity of first eliminating 

 all other kinds of variation. Thus, while it is often difficult or even 

 impossible to refer a given specimen to any particular form, a series 

 of specimens from any one locality may readily be placed, their 

 collective distinctive characters being thus brought into prominence. 

 Good series of specimens are quite necessary in reaching positive 

 conclusions in the study of the Ground Doves, and where the available 

 material has been inadequate some questions have arisen regarding 

 the status of certain forms. As in numerous parallel cases, inter- 

 gradation between the various forms is often much in evidence, and 

 must be taken into account in attempting to define their respective 

 characters and ranges. In the recognition of geographical races the 

 endeavor has been to follow a consistent and conservative middle 

 course, basing all diagnoses on evident average differences between 

 typical specimens. The following key is intended more as a tabular 

 exposition of the salient characters and relationships of the forms, 

 however, than as a practical aid in the identification of specimens. 



Key to the Species and Subspecies of Ch.emepelia. 



Based on Adult Males. 



A. Sides of the tarsus naked. (Chcemepelia.) 

 a. Breast squamate. (C. passerina.) 



b. Larger, wing averaging over 85 mm. 



c. Above plain grayish brown; below deeper vinaceous. 



C. passerina passerina, 

 c 1 . Above drab gray; below paler vinaceous. 



C. passerina pallescens. 

 c 1 . Above dull brownish olive; below intermediate vinaceous. 



C. passerina neglecta. 



4 But I do not regard this as an argument against the non-emendation of names. 



