374 



NATURAL HISTORY OF BIRDS. 



Fio. 175. — Syrinx f>f I'iojia 

 cat/ana, traoheo-brunchial. 



Fio, 176. — Syrinx of 

 Oiilro/niti, paeudo- 

 broncliint. 



distance from the bifurcation tlicy arc re]ilacctl by SL'nii-rinijs, the ends of which are 



connected by the tynipaniform membrane, whicli, therefore, is not continuous with 



any of the tracheal rings. This comlition in the cuckoos is similar to that of ^iteator- 



ni.% which is figured later on (page 385). The pseudo-bronchial syrinx, as we jiropose 



to call it, is somewhat intermediate between the above two. At some distance down 



the bronchi are the ends of the semi-rings, separated by a rather broad membrane, but 



the rings between this and the actual bifurcation are not coni])lete, and the narrow 



sj)3ce between their ends is filled by a strip of memVirane, which connects the tymp:i- 



num j)roper with the bifurcation, and 



the lower tracheal rings which may 



also be similarly inconijilete, a.s shown 



in Fig. 176. 



The true bronchial syrinx is only 



found in two peculiar -Vmerican forms, 



Crotojj/uti/a and Giiira, which also 



agi-ee in many external cliaracters, for 



instance, in being the only cuckoos 



with eight tail-feathers, all the rest 



having ten. These two are, therefore, 



fairly entitled to sub-family rank. On 



the <itlier hand, the muscular furmula 



AXY-|- is concomitant with a certain j>;ittirn of the inferior feather tract, as in the 



cuckoos which have not the muscle B, the ventral ti-act of both sides is single and not 



bifurcate. The sub-family thus characterized comprises the true Cuculina>, which 



again f.alls in two groups, those of the New Worl<l with the inferior s]>aee reaching 



quite to the symphysis of the mandible, an altogether peculiar arrangement, and the 



Old World species in which it only reaches ])art np the neck. The pterylograjdiic 



peculiarities are contrasteil in figures 177 and 178. However, on the whole, the cla.s- 



sifieation of the cuckoos is in an unsatisf.actory condition, and we therefore proceed to 



the more interesting forms without committing ourselves to any limitation of the 



minor groups. 



It is but natm-al to begin with the bird which is tlie cuckoo, from the sonorous 



voice of which the whole family derives its name. The cuckoo ( ( 'uctdtis canonis), in 



different local forms occurring all over the Palajarotic region, and wanderintj far south 



p ..... , ^ ' ^ 



m winter, is astonishingly like, in extei-n.al a])]iearanoe, some of the smaller hawks, not 



only in color, but also in its maimer of flight, a resemblance which in Euroj)e caused 

 the superstition that the young cuckoo in the autumn turns into a hawk. The male 

 bird is well represented in the accompanying cut; the back is slaty blue, throat lighter • 

 gray, rest of under side white with dusky cross-bars; feet cadmium yellow, and bill 

 dnsky, with the corner of the mouth yellow, as is also the eye. Some Oriental cuckoos 

 belonging to the nearly allied genus Jli'erococc>/x carry the Accipitrine resemblance 

 still further, as the young birds have the dusky markings on the lower surface longi- 

 tudinal, as in many hawks and f.alcons, later on, like them, changing into a j)lum!ige 

 transversely barred. This similarity is not accidental, but evidently a ca.se of protec- 

 tive mimicry, a sujiposition greatly strengtheneil by the fact that we know of some 

 small Malacean cuckoos (Pen(/iocen/.r), rusty brown above, and white beneath, barred 

 with dusky, which, in size, color, and general habits most closely ape the apjiearance of 

 certain diminutive shrikes inliabiting the same country. Still more remarkable, if 



