=_Myiarchus cinerascens cinerascens_= (Lawrence): Ash-throated Flycatcher.--A juvenal male (38975, testis 2 mm., no fat, 35.0 gm.) taken in mesquite at Camp 1 constitutes our only record for this species. Lanyon (1961:441, map) has shown that most of Tamaulipas is devoid of these flycatchers in the breeding season; the nearest known breeding Ash-throated Flycatchers are slightly west of Corpus Christi, Texas, about 200 miles north-northwest of Camp 1 on the barrier beach. Our specimen closely resembles eight specimens from Coahuila, México, in general coloration and, especially, in the pattern of colors on the outer rectrices. Probably No. 38975 was from southwestern Texas or Coahuila and had begun its southward migration. Against this idea lies chiefly the fact that young-of-the-year tend to move south later than adults of the same species; so, this bird possibly had been reared in coastal Tamaulipas. =_Eremophila alpestris giraudi_= (Henshaw): Horned Lark.--This species occurred in moderate numbers on alkaline flats and almost barren sand flats at both camps. At the time of our visit to the island, the breeding season apparently was coming to an end, but we noted no tendency in the birds to flock. Specimens (7): [M], 38981, testis 6 mm., 21.0 gm.; [M], 38977, testis 7.5 × 4 mm., not fat, 27.5 gm.; [M], 38979, testis 11 × 7 mm., 29.0 gm.; [F], 38976, ova to 3 mm., brood patch vascular but regressing, no fat, 24.4 gm.; sex? juv., 38987, no fat, 21.0 gm.; sex? juv., 38980, 24.0 gm.; Camp 1, July 7. Male, 38982, testis 9.5 × 6 mm., 27.5 gm., Camp 2, July 9. The subspecies _E. a. giraudi_, which is endemic to the Gulf coastal plain of Texas and Tamaulipas, has been reported in Tamaulipas previously only from Bagdad, near Matamoros (Mexican Check-list, 1957:106). The fact that our specimens show characters totally consistent with those of _E. a. giraudi_ indicates that there is little genetic interchange between the population we sampled and those of _E. a. diaphora_, the closest of which reportedly breeds at Miquihana, in southwestern Tamaulipas. =_Corvus cryptoleucus_= Couch: White-necked Raven.--Several groups of six to ten birds were present at Washington Beach on July 6 and 10; but, southward on the island, we recorded this species only once, on July 9, when a lone individual flew near Camp 2, being pursued and "buzzed" by two Least Terns. The Mexican Crow (_Corvus imparatus_) reportedly is common in the coastal region of Tamaulipas (Mexican Check-list, 1957:118) but was not seen by us. =_Thryomanes bewickii cryptus_= Oberholser: Bewick Wren.--This species seemingly breeds in small numbers in mesquite stands near Camp 1, where we obtained a juvenile and saw another individual. Specimen: [F] juv., 38983, no fat, 10.0 gm., Camp 1, July 8. _T. b. cryptus_ is reported to intergrade with _T. b. murinus_ of Veracruz in southern Tamaulipas (Mexican Check-list, 1957:160-161).