528 



rURPLE MARTIN. 



There is a superficial resemblance between the Swallows and the Swifts, but the relationship is 

 analogous not homologous, the difterences between the two forms being very wide. ^ Take, for e.\am|ile, the 

 sternum alone, as found in such typical species as the Barn Swallows and the Chimney Swifts. See Fig. 01, 

 where, at 1, I have given a cut of the sternum of the Barn Swallow, and compare it with ib. 2, wdiich is a cut 

 of the sternum of the Chimney Swift. The scapular, s, of the Chimney Swift is shorter than that of the 

 Swallow, the Coracoids, c, o, much shorter and stouter ; the furcula, F, shorter, well arched (See also Plate 

 XVI, fig. 15), with a very small terminal expansion ; it is bent downward and does not approach the tip of the 

 keel ; the keel. K, is high and is i erforated with a series of holes along the lower side, a character not seen in 

 the Swallows. The marginal indentations, M, so prominent in the Swallows, are absent in the Swifts. The 

 Chimney Swift also has the singular glands in the lower mandible from which it obtains the vascid fluid used 

 for fastening the sticks together with which it makes its nest. See Fig. (11, 3, where an enlarged gland is 

 "•iven, and 4, where the gland may be seen, life size, lying in the mandible. E, being the tip cf bill and T the 

 the tongue- Also compare other characters given on Plate XVI. 



Fig. fil. 1, Sternum of Barn Swallow. 2, Ster- 

 num of Chimney Swift ; s, scapulars ; F, furcula ; c o, 

 coracoids ; c ]i, costal process ; M, marginal indenta- 

 tions ; k, keel, in both figures. 4, glands in lowe^r 

 mandible of Chimney Swift ; b, bill ; t, tongue ; 3, 

 enlarged gland. 



Fig. 62. Head and foot of Adult Purple Martin. 



GENUS I. PROGNE. THE MARTINS. 



Gen. Ch. Bill, stout and large, with the upper mandible curved. Feet, stout and large. Tail, 

 moderately well forked. Sexes dissimilar. We have two species within our limits. 



PROGNE SUBIS. 

 Purple Martin. 



Hirundo subis Lmn., Syst. Nat., 10th Ed., 1758, 192. 

 DESCRIPTION. 



Sp. Ch. Size, large. Form, robust. Bill, stout ; upper mandible considerably arched. Tail, short and 

 moderately forked. Feet, stout. Sternum stoutly built. Tongue, short, thin, horny, triangular in form, tip 

 rather deeply cleft, but not ciliated. 



