K. Selander, 1954 O. nigricaudatus 48 Rancho Ocuilapa, Chiapas April 5 Some of the variations I scarcely recognized as those of the wrens, in any event the population is just about intermediate in characters between nigricaudatus and humilis and shows nearly if not the full range of variation of the two forms. Certain facts of nigricaudatus: 1 Apparently never frequents the ground. 2 Obviously found foraging high in trees. 3 Snip from high portion of tree - usually on a bare branch - apparently in an exposed position. 4 Occurs in groups of more than 2 birds -- but definitely more frequently in pairs (only) than chiapensis. 5 We do it song is similar in meter to the song of chiapensis. 6 Occasionally climb vertical or near vertical trunks of trees and I have seen humilis do on palm trees. 7 Few nests seen and I suspect that acacia is not the preferred nesting tree else we would have seen more nests on our hunts. We left Ocuilapa (after taking a shot at a good- allegator [illegible] near the river) and drove into Tonala' where we took a room at the Hotel Central and spent the remainder of the day pre- paring specimens.