50 TYRANNIDA. 
The range of this species coincides, to a great extent, with that of VW. luteiventris. 
For though it has not yet been noticed in Southern Arizona, it occurs with the allied 
species in the Sierra Madre of Tamaulipas, and thence southwards along the eastern 
slope of the mountains of Vera Cruz into Yucatan, Costa Rica, Panama, and a large 
portion of Northern South America. It has not yet been traced in Western Mexico or 
Guatemala, but is doubtless found in the latter country. 
M. nobilis is said to differ from M. audaxr in being “ brighter, and the breast-spots 
narrower,” but with the series before us we cannot fix any such difference to any 
particular district. Nor is it otherwise with W. a. insolens, the bill of which is said to 
be shorter, and the upper plumage devoid of rusty tinge. 
Mr. Sclater speaks of his M. nobilis as an intermediate form passing into WZ. lutei- 
ventris and M. audaz at the northern and southern extremities of its range. We only 
find this to be the case as regards M. audax, for we can always distinguish WV. luteiventris 
by the characters upon which Mr. Ridgway lays stress. 
The fact of two closely allied species being found together is no doubt difficult of 
explanation, and we have no solution to offer. So far as our specimens go it appears 
that the sexes are alike in both species. 
Salmon, who found the nest and eggs of M. audaw in the Cauca valley of Colombia‘, 
describes the former as made of fern-stalks and twigs, and placed in the fork of a tree 
or high bush; the eggs are white spotted with red. 
b. Corpus subtus immaculatum. 
3. Myiodynastes hemichrysus. (Tab. XXXVIII. fig. 1.) 
Hypermitres chrysocephalus, Cab. J. f. Orn. 1861, p. 246°. 
Hypermitres hemichrysus, Cab. J. f. Orn. 1861, p. 247°; Salv. P. Z. 8. 1870, p. 193°. 
Myiodynastes hemichrysus, Lawr. Ann. Lyc. N. Y.ix. p. 114°; Scl. Cat. Birds Brit. Mus. xiv. p.188°. 
Myiodynastes superciliaris, Lawr. Ann. Lyc. N. Y. viii. p. 470°. 
Supra olivaceus, uropygio fuscescentiore ; capite summo nigricanti-olivaceo, crista magna celata flava ornato ; 
superciliis elongatis et stria utrinque malari latescenti-albis; fascia lata a naribus per oculos nigra; alis 
et cauda fuscis; secundariis intimis albido extrorsum limbatis; tectricibus et primariis internis rufo 
limbatis; rectricibus utrinque rufo marginatis: subtus flavus; gula albicantiore; hypochondriis olivaceis: 
rostro et pedibus nigris. Long. tota 8:0, ale 4:0, caude 3°35, tarsi 0°75, rostri a rictu 1:15. (Descr. 
maris ex Calovevora, Panama. Mus. nostr.) 
Av, juv. cristam celatam caret. 
Hab. Costa Rica (v. Frantzius!+), Barranca (Carmiol®); Panama, Chitra, Calovevora, 
Calobre (Arcé ®). 
This species is a near ally of the Andean WM. chrysocephalus, from which it may be 
distinguished by the clearer yellow of its throat and under surface. Its range is very 
restricted, as it is not found beyond the mountains of Costa Rica and the adjoining part 
of the State of Panama. No member of this section of the genus is found on the line of 
