Paraguay , Bolivia, and Southern Brazil . 337 
197. Ardea sibilatrix. 
Ardea sibilatrix Arg. Orn. ii. p. 100. 
Syrigma cyanocephalum Sharpe, Cat. B. xxvi. p. 170. 
a. A ad. Tebicuari, Paraguay. Aug. 17, 1909. 
Irides pale bluish grey ; orbits and lores electric blue; 
bill lilac, tip black ; legs and toes black. 
This species was commonly observed on the river expedition 
in most of the swamps, usually in pairs ; and, when 
disturbed, perched on the outermost branches of the trees. 
It has a low whistling note. 
198. Butorides cyanurus. 
Butorides cyanurus Arg. Orn. ii. p. 101. 
Butorides striata Sharpe, Cat. B. xxvi. p. 175 ; Oates, Cat. 
Birds* Eggs Brit. Mus. ii. p. 126. 
a. $ ad. Babicho, Brazil. Oct. 8, 1909. 
Irides rich lemon-coloured, orbits and top of lores greenish 
yellow, rest of lores and adjoining gape dull sooty black ; 
bill black, lower basal half of lower mandible greenish 
yellow; legs and toes ashy-yellow, lemon-yellow at tibio- 
tarsal joints, behind tarsi,, and soles of feet. 
Commonly observed on the river expedition and fre¬ 
quenting the bush along the banks, usually singly. 
When alarmed this bird has a curious habit of raising 
the feathers of the head and neck, and on taking wing it 
utters a harsh grating cry. I did not obtain it in the Ajo 
district, where it is very rare, though quite a number were 
observed there by Miss Bunnacles during the summer of 
1909, and I have an adult male and two adult females 
collected by her between October 24th and November 14th. 
It also bred there that year, and eight eggs are in her 
collection taken between November 9th and 28th. 
These eggs are pale bluish green and measure: axis 1*50 
to 1*55 in., diam. IT to 1T9. 
Miss Bunnacles tells me that the full clutch of eggs 
consists of four, and that the nest is a small platform of dry 
durasnillo in a cahadon. 
