=_Sterna forsteri_= Nuttall: Forster Tern.--Six were recorded near Camp 1 on July 7, and two were seen on the beach on July 6 and 10. The Mexican Check-list (1950:108) does not cite records for Tamaulipas, but the A.O.U. Check-list (1957:234) includes northern Tamaulipas within the breeding range. Evidence suggesting breeding of the species in extreme northern Veracruz is reported by Loetscher (1955:29) in the form of a female specimen with "ovary greatly enlarged" taken seven miles west of Tampico on May 30, 1947. In the same area the species also seems to spend the summer as a nonbreeder, for Loetscher (_loc. cit._) saw 20, nearly all in nonbreeding plumage, on July 1, 1952. Specimens (4): [M], 38952, testis 4.5 mm., 150 gm., 8 P old; [M], 38955, testis 2 mm., 138 gm., 2 P old; [M], 38953, testis 5 × 1 mm., 142 gm., 5 P old; [F], 38954, ova to 1 mm., 148 gm., 2 P old; Camp 1, July 7. =_Sterna albifrons antillarum_= (Lesson): Least Tern.--The status of this species in Tamaulipas is uncertain, but there is reason to believe that it breeds, at least in small numbers. We found the species moderately common and generally flying about in twos, possibly mated pairs, near both camps and on the beach. Breeding is suggested by the large sizes of the testes of the two males collected and by the presence of brood patches on a female taken on July 6, but we have no direct evidence of nesting in Tamaulipas, and it should be noted that this species is known to spend the summer in nonbreeding condition at many places (A.O.U. Check-list, 1957:239). Loetscher (1955:30) suggests that the species may be found breeding in Veracruz and mentions a record of 15 seen at Miramar, Tamaulipas, on June 26, 1952. Dresser (1866:45) found it to be "abundant" at the "Boca Grande" in summer. On July 10, we saw flocks of 15 to 20 individuals flying along the beach a few miles south of Washington Beach. Specimens (4): [M], 38958, testis 11 × 4 mm. (right testis 5 × 4 mm.), light fat, 45 gm., 6 P old; [M], 38959, testis 11 × 4 mm. (right testis 7 × 4 mm.), light fat, 45 gm., 6 P old; [F], 38956, ova to 2.5 mm., 42.5 gm., 6 P old, brood patches refeathering; Camp 1, July 6. Female, 38957, ova to 1 mm., 44 gm., Camp 1, July 7. This last specimen had essentially completed the autumnal molt into winter plumage, with only a few feathers remaining ensheathed basally. Our specimens are referable to _S. a. antillarum_, being paler dorsally and slightly lighter gray on the hind-neck than specimens of _S. a. athalassos_ from Kansas, with which they were compared.