This sub-region is well characterised by its almost exclusive possession of _Ectopistes_, the celebrated passenger pigeon, whose enormous flocks and breeding places have been so often described; and _Cupidonia_, a remarkable genus of grouse. The only Nearctic parrot, _Conurus carolinensis_, is found in the Southern States; as well as _Crotophaga_, a South American genus usually associated with the cuckoos. _Helmintherus_ and {133}_Oporornis_, genera of wood-warblers, may be considered to be peculiar to this sub-region, since in each case only one of the two species migrates as far as Central America; while two other genera of the same family, _Siurus_ and _Setophaga_, as well as the finch genus, _Euspiza_, do not extend to either of the western sub-regions. _Parus_, a genus of tits, comes into the district from the north; _Otocorys_, an alpine lark, and _Coturniculus_, an American finch, from the west; and such characteristic Nearctic genera as _Antrostomus_ (the whip-poor-will goatsuckers); _Helminthophaga_, _Dendræca_, and _Myiodioctes_ (wood-warblers); _Vireo_ (greenlets); _Dolichonyx_ (rice-bird); _Quiscalus_ (troupial); _Meleagris_ (turkey); and _Ortyx_ (American partridge), are wide-spread and abundant. In Mr. J. A. Allen's elaborate and interesting paper on the birds of eastern North America, he enumerates 32 species which breed only in the more temperate portions of this province, and may therefore be considered to be especially characteristic of it. These belong to the following genera:--_Turdus_, _Galeoscoptes_, _Harporhynchus_, _Sialia_, _Dendræca_, _Wilsonia_, _Pyranga_, _Vireo_, _Lanivireo_, _Lophophanes_, _Coturniculus_, _Ammodromus_, _Spizella_, _Euspiza_, _Hedymeles_, _Cyanospiza_, _Pipilo_, _Cardinalis_, _Icterus_, _Corvus_, _Centurus_, _Melanerpes_, _Antrostomus_, _Coccyzus_, _Ortyx_, and _Cupidonia_. _Reptiles._--In this class the Eastern States are rich, possessing many peculiar forms not found in other parts of the region. Among snakes it has the genera _Farancia_ and _Dimodes_ belonging to the fresh-water snakes (Homalopsidæ); the South American genus _Elaps_; and 3 genera of rattlesnakes, _Cenchris_, _Crotalophorus_, and _Crotalus_. The following genera of snakes are said to occur in the State of New York:--_Coluber_, _Tropidonotus_, _Leptophis_, _Calamaria_, _Heterodon_, _Trigonocephalus_, _Crotalus_, _Psammophis_, _Helicops_, _Rhinostoma_, _Pituophis_, and _Elaps_. Among lizards, _Chirotes_, forming a peculiar family of Amphisbenians, inhabits Missouri and Mexico; while the remarkable glass-snake, _Ophisaurus_, belonging to the family Zonuridæ, is peculiar to the Southern States; and the South American _Sphærodactylus_, one of the gecko family, reaches Florida. Other genera which extend as far north as the State of New {134}York are, _Scincus_, _Tropidolepis_, _Plestiodon_, _Lygosoma_, _Ameiva_, and _Phrynosoma_.