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Show 1878.] MR. A. BOUCARD ON BIRDS FROM COSTA RICA. 61 Subfamily FORMICIVORIN.E. 181. M Y R M O T H E R U L A 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),Tardidss (several genera) and Dendrocolap-tidae (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-bidae, and Ampelidae, 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. RAMPHOCCENUS SEMITOROUATUS, Lawr. One specimen, from San Carlos, February. Very rare. Perch on small 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 passing 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. |