_Myiarchus tyrannulus cooperi_ Baird: Wied Flycatcher.--This species was especially common among the coco palms on Isla del Carmen and Isla Cozumel. Specimens (5): [Male], 40667, 36.7 gm. (July 8), [Male], 40668, 36.6 gm. (July 8), sex? 40669, 39.4 gm. (July 8), and [Female], 40670, 37.3 gm. (July 8), all from 1 km. SW Puerto Real, Isla del Carmen; [Female], 40666, ovary inactive, 34.9 gm. (August 10), 3 km. N San Miguel, Isla Cozumel. _Myiarchus tuberculifer platyrhynchus_ Ridgway: Olivaceous Flycatcher. --Breeding specimens of this species have been known previously from April and May (Paynter, 1955a:196); records listed beyond extend the season nearly three months. Specimens (7): [Female], 40673, ova to 5 mm. (July 10), and [Female], 40674, ovary 7 × 3 mm. (ova to 1 mm.) (July 11), 5 km. SW Champotón; [Female], 40745, ovary inactive, 17.5 gm., starting to molt--1st, 2nd, and 3rd primaries ensheathed (July 16), 7-1/2 km. W Escárcega; [Female], 40671, imm., 16.1 gm. (July 20) Cenote Seco, 2 km. E Chichén-Itzá; [Male], 40746, 18.2 gm. (July 22), Pisté; [Female], 40672, ovary inactive, 17.7 gm., molting--5th and 6th primaries and 1st secondaries ensheathed (August 15), 4 km. NNE Felipe Carrillo Puerto; [Male], 40675, left testis 13 mm., right testis 10 mm., 17.5 gm. (August 8), 3-1/2 km. N San Miguel, Isla Cozumel. _Contopus cinereus_ (Spix): Tropical Pewee.--The regressing gonads of the male taken on July 21 in an early stage of molt suggests breeding on the peninsula. Specimens (2): [Male], 40676 testis 6 × 3 mm., 11.5 gm., starting to molt--1st and 2nd primaries ensheathed (July 21), 6-1/2 km. W Pisté; [Male], 40677, testis 1 mm., 12.6 mm., molting--4th, 5th, and 6th primaries and 2nd secondaries ensheathed (August 14), 4 km. NNE Felipe Carrillo Puerto. _Tolmomyias sulphurescens_ (Spix): Sulphury Flat-Billed Flycatcher.-- Paynter (1955a:201) presented breeding records for this species from mid-April to late June. My specimens seem to indicate that breeding extends at least into July. Specimens (6): [Female], 40683, juv., 14.0 gm. (July 21), [Male], 40684, juv. (remiges and rectrices ensheathed basally), 14.0 gm. (July 21), and [Male], 40682, testis 8 × 4 mm., 13.7 gm. (July 26), Pisté and 3-1/2 km. N Pisté; [Male], 40685, testis 7 × 4 mm., 15.3 gm., molting--1st and 2nd primaries ensheathed (July 28), and [Female], 40686, ovary inactive (July 28), Pueblo Nuevo X-can; [Male], 40687, imm., 16.0 gm. (August 15), 4 km. NNE Felipe Carrillo Puerto. Mallophaga: _Philopterus_ sp. July 28; _Myrsidea_ sp. July 28. _Myiopagis veridicata_ (Vieillot): Yellow-crowned Elaenia.--The only previous breeding record is of a male that was taken on April 29. My only specimen has nearly fully enlarged testes. Specimen (1): [Male], 40688, testis 7 × 4 mm., 13.1 gm. (July 17), 1 km. N, 13 km. W Escárcega.