The plethodontid salamander Bolitoglossa mulleri (Brocchi) is a member of the Bolitoglossamexicana species group and is known to occur in tropical and subtropical forests (approximately 100 to 1,500 m elev.) on the Gulf versant of Guatemala (Elias, 1984). The major taxonomic character differentiating B. mulleri from other members of the species group is color pattern. The species varies from uniform black above to possession of one median narrow light stripe of different intensities (Stuart, 1948; Elias, 1984). The median light stripe is fully developed, extending from the tail tip to the neck, then bifurcating and ending on each eyelid; partially developed, ending on the neck; or reduced and variably discontinuous throughout the body. Bolitoglossa mulleri has been reported as inhabiting both terrestrial (under logs and stones) and arboreal (bromeliads) microhabitats (Stuart, 1948; Elias, 1984) and may switch preference with seasonal moisture availability (Duellman, 1963), as is common with other members of the B. mexicana species group (Wake and Lynch, 1976). Actually, Duges (1896) and Smith and Smith (1976) reported the species from Chiapas without giving a precise locality. However, MaldonadoKoerdell's (1948:221) description of Duges (1896) specimens cleariy indicates that they belong to Bolitoglossa odonnelli and not to B. mulleri: "Both specimens are adults, of very dark coloration, slightly less on the ventral surface, with yellowbrown lines on both sides of the body, from the eyes to the base of the hind limbs and with clearer rings, highly irregular on the initial portion of the tail." Much of the confusion regarding the taxonomic status of B. mulleri may be attributed to Brocchi's (1883) original description, since only one (fig. 4) of the three figures (figs. 3, 4 and 5)