119* BIRDS OF ILLINOIS. 



Seyeral of the above are unquestionably good genera; but 

 having announced my determination to follow the A. 0. U. 

 classification and nomenclature in this work I am obliged to 

 do so in this case. With the exception of Dichromanassa and 

 Hydranassa (which are related most nearly to Demiegretta, of south- 

 eastern Asia, Polynesia, etc.) and Florida, all the groups are 

 cosmopolitan, being represented in different regions by distinct 

 species, all agreeing minutely in structural characters. Butorides, 

 for example, has, besides the North American species, one in 

 Cuba, another in South America, a third in the Galapagos Archi- 

 pelago, and several others in various parts of the eastern hem- 

 isphere. 



Subgenus Ardea Linnaeus. 



Ardea Linn. S. N. ed. 10, i. 1758. 141. Type, by elimination, A. cinerea Linn. 



Subgen. Chab. Herons of largest size (of Stork-like stature), the adults distinguished 

 by lengthened, narrowly-lanceolate, acute jugular and scapular plumes (the former rather 

 rigid, the latter overhanging the wings and rump); a tuft of broad feathers on each side the 

 breast (having a different color from adjacent parts), and, in the breeding season, by the 

 presence of two or three extremely lengthened, narrow, pendant, c ccipital plumes. 



Culmen almost straight; gonys ascending, slightly convex, about equal in length to 

 the mandibular rami ; upper and lower outlines of the bill parallel for the basal half. Mental 

 apex anterior to half-way between point of bill and anterior angle of the eye; frontal apex 

 a little posterior to the nostrils and a little anterior to the malar apex.* Middle toe more 

 than half the tarsus, and about equal to bare portion of tibia; outer toe reaching to abouc 

 the middle of the penultimate phalanx of the middle toe; inner toe decidedly shorter, 

 reaching only to the second articulation of the middle toe; hallux a little longer than the 

 basal phalanx of the outer toe ; claws rather short, strongly curved. Front of tarsus with 

 broad, transverse scutellaa, in single series, for upper half. Pileum crested, the feathers of 

 the crown and occiput being elongated, lanceolate, and decurved. Primaries reaching de- 

 cidedly beyond tertials. Second, third, and fourth quills nearly equal, and longest; first 

 longer than fifth; inner webs of outer three slightly sinuated near ends. 



Synopsis of Species. 



a 1 . Color of plumage entirely pure white. Hab. Southern Florida A. oecidentalis. 



a*. Color of plumage chiefly bluish or grayish. 



6 1 . Adult with head entirely white, except (usually) black or dusky streaks on fore- 

 head, or (rarely), a blackish patch on sides of crown or occiput, beneath edge of 

 crest; more white on under parts, edge of wing, etc. Hab. Southern Florida: 



accidental in southern Illinois A. wuerdemannii. 



& a . Adult with top of head, including occipftai plumes, black, with a large white patch 



covering forehead and center of crown; more black on lower parts and more 



rufous on edge of wing. 



c 1 . Larger, with legs and feet yellowish brown or olive-yellowish ; total length, about 



48 to 54 inches; wing, 19.50-21.00; exposed culmen, 5.90-0.90 ; tarsus, 7.85-8.40. 



Hab. Florida .«— A. wardi. 



* The terms "mental apex", "malar apex", and "frontal apex" are here employed to de- 

 note the apices, or points of the feathering of the head at the base of the bill. 



