446 ICTERIDZ. 
is @ very common species within our region. Amblycercus has been placed both with 
Cassicus and Cassiculus, but no doubt it has characters to distinguish it from both those 
genera. In the first place the nostrils are covered by a hard horny operculum, leaving 
the nasal orifice a comma-shaped slit, the tail of the comma being directed outwards. 
This structure is not found in the more normal Cassicine, and we have had to modify 
My. Sclater’s characters in order to include Amblycercus. This operculum is not like 
the membranous covering of the nostril in the other subfamilies of Icteride, being as 
hard and horny a substance as the sheath of the bill itself. The culmen is straight, 
and the points of the jaws rounded horizontally and flattened; the feet are stout, and 
the tarsi comparatively longer than in Cassicus. The wings are short and very much 
rounded; the fourth, fifth, and sixth quills are subequal, and slightly longer than the 
seventh, eighth, and ninth, the third equals the seventh, the second is about equal to 
the longest secondaries, and the first is much shorter still. The tail is much rounded. 
The short, rounded wing presents another obvious point of difference from Cassicus 
and Cassiculus. 
As in Cassiculus the feathers of the lower back are normal, the barbs being fully 
furnished with barbules. 
1. Amblycercus holosericeus. 
Sturnus holosericeus, Licht. Preis Verz. Mex. Vog. p. 1 (cf. J. £. Orn. 1863, p. 55)*. 
Cacicus holosericeus, Salv. Cat. Strickl. Coll. p. 262°. 
Cassicus holosericeus, Scl. Ibis, 1883, p. 163°; Boucard, P. Z. 8. 1883, p. 445*; Tacz. Orn. Pér. ii. 
p. 415°. 
Amblycercus holosericeus, Scl. Cat. B. Brit. Mus. xi. p. 327°. 
Amblyramphus prevosti, Less. Cent. Zool. p. 150, t. 547. 
Amblycercus prevosti, Cab. J. f. Orn. 1861, p. 10°; Cass. Pr. Ac. Phil. 1867, p. 73°; Lawr. Ann. 
Lye. N. Y. ix. p. 104"; Frantz. J. f. Orn. 1869, p. 302". oe 
Cassiculus prevosti, Scl. P. Z. 8. 1856, p. 301"; 1859, pp. 365", 880%; 1860, p. 276”; 1864, 
p. 174; Scl. & Salv. Ibis, 1859, p. 197; 1860, p. 34°; P. Z. S. 1864, p. 853”; 1870, 
p. 886; Moore, P. Z. 8. 1859, p. 57"; Lawr. Ann. Lye. N. Y. vii. p. 297”; Ann. Lye. 
N. Y. vii. p. 180%; Salv. P. Z. S. 1867, p. 1427; 1870, p. 190”; Sumichrast, Mem. 
Bost. Soc. N. H. i. p. 553°°. 
Cassicus prevosti, Lawr. Bull. U. 8. Nat. Mus. no. 4, p. 23”; Nutting & Ridgw. Pr. U.S. Nat, 
Mus. vi. pp. 383%, 402”. 
Cassicus, sp.?, Bp. P. Z. 8. 1837, p. 115°. 
Nigerrimus, unicolor; rostro eburneo, pedibus nigris. Long. tota 9°5, alee 4:2, caudes 4:4, rostri a rictu 1:2, 
tarsi 1-3. (Descr. exempl. ex Jalapa, Mexico. Mus. nostr.) 
© mari similis. 
Hab. Muxico" (Deppe*, Sallé*), valley of Mexico (White 16), hot and temperate regions 
of Vera Cruz (Sumichrast?°), Jalapa (de Oca), Teotalcingo and Playa Vicente 
(Boucard'*), Guichicovi, Sta. Efigenia (Swmichrast?"), Yucatan (Gaumer *); Britise 
Honpuras, Belize (Blancaneaux); Guatemana (Velasquez, Constancia 2), Yzabal 18, 
