Loral feathers verj^ compact, imbricated, aucl without bristly 

 tips. Tomia not toothed Pernis. 



Loral feathers moderately compact, or even scattered, not imbri- 

 cated, and with bristly tips. Tomia toothed. 



§. Four outer primaries with iauer webs sinuated Leptodon. 



§. Two outer i)riraaries with inner webs sinuated Baza. 



h. Bill greatly hooked, and much couipressed. Feathers of the 

 pileum soft and blended, without tendency to greater elouga- 

 tiou ou the occiput. Lores naked, crossed by a narrow line of 

 fine bristles from the anterior angle of the eye to the fore- 

 head EecjerMnns. 



B. Cere not tumid, the nostril broad}' oval, without overhanging 

 membrane. Tail excessively forked, about equal to the wing. 

 Inner webs of only two outer quills sinuated. Tomia with- 

 out iudentations. Lores densely feathered Elanoides. 



The transition from Leptodon to Baza., through Avieida, may be ex- 

 pressed by thefollowiug tabulation of the maiu characters of the three 

 genera : 



A. Five outer primaries with inner webs sinuated. 



a. Tail much rouuded. Primaries but little longer than secondaries. 

 Lores scantily feathered. Indentations of the tomia a simple 

 tooth and notch. Occipital crest rudimentary Leptodon. 



h. Tail nearly even. Primaries considerably longer than the secon- 

 daries. Lores scantily or compactly feathered. Indentations 

 of the tomia simple or double. Occipital crest rudimentary or 

 moderately developed Avicida.* 



B, Two outer primaries with their inner webs sinuated. Loral 



feathers very compact. Indentations of the tomia double. 



Occipital crest very long Baza. 



The apparently wide difference between Leptodon and Pernis in the 

 feathering ot the lores is most perfectly made up by the varying character 

 of the species in the genus (or subgenus) Avicida, the three species w^e 

 have been able to examine varying as follows: — 



A. suhcristata. — Loral feathers compact. Indentations of the tomia 

 double. 



A. verreauxi. — Loral feathers scant. Indentations of the tomia double. 



A. cucidoides. — Loral feathers scant. Indentations of the tomia 

 simple. 



Thus, in A. suhcristata, the loral feathers are only a little less compact 

 than in Baza, in which they are rather less dense than in Pernis. In 

 the other two species they are still less dense, though more so than in 

 Leptodon (as most restricted) ; while one of the species of Avicida agrees 

 with Leptodon in the simple indentations of the tomia. Nearly all of 

 these birds, including Pernis, have more or less of a tendency in a few 

 of the occipital feathers to form a crest, which in Leptodon is constantly 

 rudimentary, and in the species of Avicida and Pernis frequently so. 



LEPTODOX CAYENXEXSIS. 



I'ulco cai/enneiisis Gmelix, Svst. Xat. i, 17S8, 269 (not of p. 2B3I), (adult). — Lath. 

 judex Orn. i, 17110, 28; Gen. Hist, i, 1824, 2G9.— Daud. Tr. Orn. ii, ISUO, 74.— 

 SiiAW, Zoul. vii, 161.— Temm. PI. Col. i, lb24, pi. 270 ; Tab. Moth. 4. 



' Jvicida Swaixson, Birds W. Africa, i, 1837, 104. Type, A. ciicitlokks Swains. 



This genus iuchules also A. siibcristatus (Gould) and A. verreauxi Lafr., and probably 

 others, since Mr. Sbarpe includes in the genus ^'Baza'' ten species, of which we cannot 

 state positively that more than one, B. Jophoie", is a true Ba:a, not having seen most 

 of the species described. 

 No. 2 5 



