64 PTERYLOGRAPHY. 



peculiar to this group, but are not so perfectly marked in any other. The large and very 

 strong eyelashes, of which I have counted thirty in the .upper and half that number in the lower 

 eyelid, appear to stand in relation to this, for I find them always much developed in naked- 

 cheeked Falcons, and, on the contrary, small in those in which these parts are feathered. Beak 

 without any denticulation or angle on the margin of the upper mandible, exactly as in Morpknus, 

 Polyborus and Buteo, and also of the same comparative size ; much more powerful than in Pernis, 

 Astur, Milvus, and Circus, in which genera a more or less perceptible angular emargination 

 of the margin of the upper mandible usually occurs. 



7. PERNIS. 



F. apivorus (Plate II, fig. 4). Lores and region of the eyes densely feathered, even to the 

 eyelids, which are quite destitute of lashes. The pterylosis exactly as in Buteo ; the outer branch 

 of the pectoral tract quite free, with a notable terminal hook; the inner branch at the end of the 

 gular portion more distinct and longer. Dorsal portion of the spinal tract with two divergent 

 rows of feathers, which reach to the scapular fork; elsewhere narrow. Remiges twenty-four, 

 sometimes one less ; the first scarcely so long as the seventh, the second longer than the sixth, the 

 third but little shorter than the fourth, Avhich is the longest; only the first three exhibit a 

 diminution of the inner vane, commencing low down towards the base. 



8. ASTUR. 



Of this group I have examined F. palumbarius, F. nisus, F.gabar (TEMM. PI. Col., 122), and 

 F, nitidus LATH. (F. striolatus TEMM., PL Col, 87). In the pterylosis I found everything as in 

 Pernis, except that the outer branch of the pectoral stem appears to be somewhat shorter, but at 

 the same time more closely approximated at the base to the equally broad stem : on the other 

 hand, the terminal hook and the inner branch are equally distinct. The lumbar tracts are either 

 entirely wanting, or consist, as in Pernis, only of a single row of a few feathers. The wings reach 

 to the commencement of the tail, and contain from twenty-three to twenty-six remiges ; the first 

 is often scarcely equal to the tenth, the second to the seventh or eighth, the third to the sixth, 

 and the fourth to the fifth : the fourth is, however, usually a little longer, and is then the 

 longest of all. The first five or six present a gradually decreasing narrowing of the inner half of 

 the vane. 



9. MILVUS. 



Pterylosis not peculiar ; inner branch on the jugular part distinct, but short ; outer branch 

 entirely free, with a perceptible terminal hook. Dorsal portion of the spinal tract usually long. 

 Remiges remarkably long, very acute, the third and fourth the longest, the first as long as the 

 seventh or eighth ; from three to five of the first with a strong, deeply-seated angular emargi- 

 nation, followed by a diminution of the inner half of the vane. 



