BIRDS OK NORTH AND MIDDLE AMERICA. 25 



in warmer countries. In the lutest .special treatise on the runiily" one 

 hundred and nine species, belonoing to twelve genera, are recognized, 

 of which thirtA'-one species and six genera'' are American— all but one 

 of the formei- and two of the latter being peculiar to the Western 

 Hemisphere. 



The number of American genera of Ilirundinida' is a question very 

 difficult to determine. As already stated, the most recent authorit}' 

 allows but six — l\ogne^ Petrochelidon^ Afticora, Stelgldopteryx^ Clim- 

 cnla, and lUrundo — and these are the genera which are generally 

 accepted. The second, fifth, and sixth of these are cosmopolitan in 

 range; the first, third, and fourth being peculiar to America. It is 

 chiefly with respect to the first, third, and sixth that the ciuestion of 

 generic homogenity is concerned; and I am convinced that each of 

 these should be subdivided if we are to have generic groups which 

 are naturally circums(;ribed. Certainly Attieora, as usually under- 

 stood, is a most heterogeneous group, and cannot be defined by any 

 charact(>r or combination of characters, while most of the eight or 

 nine species composing the artificial group in question differ from 

 one another so much in details of form that they ma\' easih^ be segre- 

 gated into seven lesser groups (mostly monotypic), each of which 

 diflers from any other in structural characters ([uitc as tangible as 

 those which distinguish other recognized genera. On the other hand, 

 if left together, the group thus formed has nothing to hold it together, 

 the species having little in common bej'ond the roundish vertical 

 nostrils (shared also b}' Progne^ PJiseoj^rogne^ Petrochelidon^ and 

 Stelgldoj^teryx') and the relativeh' long tarsus. 



The other group concerned is that included by Sharpe and others 

 in lliriDuJo. This genus, properly restricted, is, in the main, an 

 exceedingly natural one, though its limits as to Old World species 

 (man}^ of which I have not been able to examine) are uncertain; but 

 there is no question in my mind that the purely American types, 

 comprising species which, while differing much among themselves in 

 details of external structure, are all different in this respect as well as 

 style of coloration from all Old World species of IL'ruudo, should l)e 

 removed from that oemis. 



«A Monograph | of the | Hirundinidfe | or | Family of Swallows. | By R. Bowdler 

 Sharpe, LL. D., F. L. S., F. Z. S., FAc, | . . . [=(5 lines of additional titles] | and | 

 Claude W. Wyatt, | Member of the British Ornitholosists' Union. | —Volume 1 

 [-II] I — I London: | Henry Sotheran & Co., | 37 Piccadilly, W. | 140 Strand, W. 

 C. I 1885-1894. 2 vols., 4to, Vol. I, pp. i-lxx l I-356, pll. i-liv; Vol. II, pp. 

 i-viii + 357-673, pll. Iv-cxxix. 



'' Both genera and species are, however, given wider limits by Sharpe and Wyatt 

 than the facts seem to warrant. 



''In this connection it should be remend)ered that the roughened edge of the outer- 

 most piimary, so ilistinctive of adult males of Stehjidoptcrijx, often does not exist in 

 adult females. 



