206 FORMICARIIDZ. 
3000 feet. From the State of Panama we have received specimens both from the 
district of Chiriqui and from Calovevora, lying further in the direction of the isthmus, 
but the bird has not been noticed on the line of railway nor to the southward. The 
Panama birds are a little darker on the upper surface than the types, and thus approach 
the Ecuador form, which has been separated by Mr. Sclater as Thamnistes equatorialis. 
The last-named bird is very closely allied to 7. anabatinus, and the existence of an 
intermediate form indicates that there is probably no specific difference. 
Of the habits of this species nothing has been recorded; our Guatemalan specimens 
were secured by Indian hunters. 
b". Rostrum debile, leviter hamatum. 
DYSITHAMNUS. 
Dysithamnus, Cabanis, in Wiegm. Arch. f. Naturg. 1847, xiii. p. 223; Scl. Cat. Birds Brit. Mus. 
xv. p. 219. 
Dysithamnus is closely allied to the smaller forms of Thamnophilus, and there seem 
to be no obvious characters by which to distinguish them. ‘The bill is certainly some- 
what feeble, but when the size of the birds is considered this point loses its value. The 
bill, as well as the wings and legs, conform to those of such species as Thamnophilus 
nevius. The tail seems less rounded. 
Mr. Sclater places fourteen species in Dysithamnus, and mentions the names of two 
others unknown to him. These are distributed over a wide area, extending from 
Guatemala to South Brazil. Only three species occur within our region, of which 
D. semicinereus has a wide range. The other two are both peculiar to the southern 
section of our Fauna, both occurring in Costa Rica and one of them in the State of 
Panama. 
a. Pileus unicolor. 
1. Dysithamnus semicinereus. 
Dysithamnus semicinereus, Scl. P. Z.S. 1855, p. 90, t. 97*; Cat. Birds Brit. Mus. xv. p. 2217; 
Scl. & Salv. Ibis, 1860, p. 899°; Salv. P. Z. 8. 1867, p. 144*; 1870, p. 194°; Lawr. Ann. 
Lyc. N. Y. ix. p. 107°; Boucard, P. Z. S. 1878, p. 60" ; Tacz. Orn. Pér. ii. p. 29°; Zeledon, 
An. Mus. Nac. Costa Rica, 1887, p. 114°. 
Olivaceo-cinereus, capite summo unicolore pure cinereo; alis et cauda dorso concoloribus ; tectricibus alarum 
minoribus nigris, his et reliquis anguste albo limbatis: subtus cinereo-albicans, pectore obscuriore ; hypo- 
chondriis vix olivaceo lavatis; subalaribus et remigibus intus albis flavido tinctis: rostro et pedibus 
plumbeis. Long. tota 4°5, ale 2°3, caudee 1°55, rostri a rictu 0°67, tarsi 0°75. 
? supra fuscescens haud cinereo tincta; alis et cauda concoloribus, hujus tectricibus apicibus pallidis ; capite 
summo rufescente unicolore: subtus ochraceo-alba, gula fere alba, pectore et hypochondriis fusces- 
centibus: rostro et pedibus plumbeis. (Descr. maris et femine ex Vere Pacis septentrionali. Mus. 
nostr.) 
