28 BULLETIN So, UNITED STATES NATIONAL MUSEUM. 



b. Lower part of tarsus with a tuft of small feathers on inner side; claws larger and 

 sharper, those of lateral toes reaching to or beyond base of middle claw, that 

 of the hallux nearly as long as (sometimes longer than) the digit; above brown- 

 ish gray; beneath white with a brownish gray band across chest. 



Biparia (p. 72) 



66. Lower part of tarsus without any feathers; claws smaller, less acute, those of 



lateral toes falling decidedly short of base of middle claw, that of hallux 



much shorter than the digit; upper parts not brownish gray, or else« under 



parts white without grayish band across chest. 



c. Nasal operculum more or less naked and exposed. 



d. Nasal operculum with only the extreme posterior portion feathered, the 



feathering of frontal antise scarcely extending to middle of nostril; tail 



two-thirds as long as wing,* or more, forked for more than one-third its 



length, !> the rectrices with a white spot on inner web;* upper parts with 



chestnut or rufous on pileum or rump, or both; under parts with more or 



less of rufous or chestnut, or else white with a black band across chest. 



Hirnndo (p. 76) 

 dd. Nasal operculum mostly feathered, the feathering of frontal antiae extend- 

 ing to beyond middle of nostrils; tail less than two-thirds as long as wing 

 (usually much less), forked for less than half its length, the rectrices 

 without white spots on inner webs; upper parts without any chestnut; 

 under parts entirely white, or else with dusky spots on chest and throat 

 or shaded with gray on chest, 

 e. Tail less than half as long as wing, forked for less than one-fourth its 

 length, the lateral rectrices not narrower than the rest, not attenuate; 

 tarsus little, if any, longer than middle toe without claw; tibial feathers 

 longer, completely covering tibio-tarsal joint. 

 /. Lateral toes longer and stronger, their claws reaching very nearly to 

 base of middle claw; wing very little more than twice as long as tail; 

 upper parts glossy steel blue or green or glossy dark blue, the rump 



sometimes white Iridoprocne (p. 85) 



ff. Lateral toes smaller and weaker, with claws falling very decidedly 

 short of base of middle claw; wing two and a half times as long as 

 tail; upper parts opaque green, bronzy, and violet. Tachy cine ta (p. 92) 

 ee. Tail more than half as long as wing, forked for more than one-third its 

 length, the lateral rectrices narrower than the others, decidedly atten- 

 uate; tarsus decidedly longer than middle toe without claw; tibial 

 feathers shorter, not entirely covering tibio-tarsal joint. (Upper parts 

 opaque greenish, the plumage structurally similar to that of Tachycineta. ) 



Callichelidon (p. 98) 

 cc. Nasal operculum entirely feathered, the feathering of frontal antife extend- 

 ing to anterior end of nasal fossae and partly covering nostrils. (Plumage 

 of upper parts brilliantly metallic bronzy green or coppery. ) 



Lamproclielidou (p. 100) 



Genus PROGNE Boie. 



Progne Boie, Isis, 1826, 971. (Type, Hirundo purpurea Linnaeus, = if . si 



Linnaeus. ) 

 Procne (emendation) Dbs Murs, in Chenu's Encycl. d'Hist. Nat. Ois., ii, 1854, 



229. 



o In young of Tachydnda, Iridoprocne, and Callichelidon. 



^Except in some Old World species, to which, however, the other color-characters 

 given do apply. Possibly some of these aberrant species may not be really congeneric. 



