1878.] MR, A. BOUCARD ON BIRDS FROM COSTA RICA. 61 



Subfamily Formicivorin^s. 



181. Myrmotherula mel^ena, Sclat. 



Only one specimen of this fine species. It seems to be very rare. 

 I killed it in the forest perched near the ground. It formed part of 

 a large flock of birds which was not a single moment at rest. As I 

 said before, it is a very common occurrence to see large quantities of 

 ants where these birds are. I have always observed that the Tana- 

 gridae (genus Buarremon),Tur&\das (several genera) and Dendrocolap- 

 tidse (all the genera) and a few others keep to the ground, feeding on 

 ants and other insects. At the same time birds of other genera, as 

 Tanagra, Calliste, Pipra, and of many genera of Tyrannidae, Ccere- 

 bidfe, and Ampelidse, are perched on the trees above, some of them 

 feeding on fruit, others on insects. All of them are constantly flying 

 about all the time. 



But the most interesting fact is that every species follows the same 

 route. They travel rather fast ; and it has always been an object of 

 admiration to me to see how far they could travel in one day, taking 

 their food at the same time. 



I was in the habit of searching for one of these flocks. Once 

 found, it was only a matter for me of selecting what species I wanted ; 

 but you must follow the same route as they, and occasionally you 

 may lose yourself in the forest. These remarks apply to species 

 found in the tropical forests from the level of the sea to the altitude 

 of 4000 feet. But I have also observed the same thing with the 

 species which inhabit higher altitudes, whether they live in the 

 forests or on the plains. 



182. Myrmotherula menetriesi, d'Orb. 

 One specimen, from Naranjo, April. 



183. Formicivora boucardi, Sclat. 

 San Carlos, February. 



Rather rare. 



184. Ramphoccsnus semitorquatus, Lawr. 



One specimen, from San Carlos, February. Very rare. Perch on 

 Bmall trees in the forest. It was with the flock spoken of above. 



185. Cercomacra tyrannina, Sclat. 

 San Carlos, February. 



186. Myrmeciza immaculata, Sclat. and Salv. 



Several specimens, from San Carlos, February, and San Mateo, 

 May. Rare. 



This species is found on both sides of the country — I mean, in the 

 tropical forests of the Atlantic and Pacific plains. It is therefore 

 very probable that tropical species travel from one sea to the other 

 where they have the facility to do so, without the necessity of pass- 

 ing to a higher altitude ; and this is the case in Costa Rica. In a 

 certain part of the country you can pass from one sea to the 

 other without leaving the tropical forests. 



