Wagler managed to keep the various descriptions on the blue macaws separate in this slim volume, which was highly regarded in the early part of the 19th century.

43. S. hyacinthina. Maxima; rostrum ingens, edentatum corneo-nigrum; facies tota plumosa, excepta stricta arte trigona regionis paroticae ac baseos rostri, cum mento nuda flava; palpebrarum margo niger; ptilosis, tota laetissime hyacinthino violacea, alteri luci opposita intense coerulea; alae ac cauda subtus nec non alarum tectrices inferiores majores (minores coeruleae) nigrae; limbus remigum internus nigricans, harum ac rectricum rhachis atra; tectrices alarum superiores minores limbo apicali nigro. Mas et Foem, adult.

Psittacus augustus Shaw. Mus. Lever. P.59 (fig. satis accur.) Id. Misc. t. 609. (fig pessim). Psittacus hyacinthinus Lath., Bechst., Kuhl. Macrocercus hyacinthinus Vieill. Gal. Des Ois. Part 2. p. 3. t.24, Aodorhynchus Maximiliani Spix Av. Brasil. I. T. 1. (fig. opt.).

Cera maxillae prope frontem solummodo conspicua, strictissima, mandibulae latissima, in medio 7"'lata; maxiliae culmen compressuisculum, obsolete biangulosum; hujus uncus longissimus, strictus, lateraliter non emarginatus; mandibula robustissima latere anteriori convexo-compressiuscula, lateribus subapplanata, ad tomiorum medium sinuata; irides fusco-atrae; lingua nigra; pedes nigri; ungues corneo-fusci; unguis digiti antici externi arcuatus longissimus; cauda longissima, admodum gradato-lanceolata; alae longiusculae, acutae. Longitudo 381/2", caudae 21",, alae 163/4", rostri ad frontem 43/4" (hujus ambitus prope basin 9"), tarsi 19"', digiti antici externi, excluso ungue, 21/4", unguis 13/4". Habitat in Brasilia, in palmetis retro flumen St. Francisci; in provinciis Minarum et Goyazana per paria, attamen gregaria in una eademque sylva nidificans. (Mus. Monac. collect.dom. Sturm.).