PROC. BIOL. SOC. WASH. 98(1), 1985, pp. 204-220 THREE NEW SPECIES OF THREAD SNAKES (SERPENTES: LEPTOTYPHLOPIDAE) FROM HISPANIOLA Richard Thomas, Roy W. McDiarmid, and Fred G. Thompson Abstract.— Three new species of thread snakes of the genus Leptotyphlops are described from Hispaniola as: L. calypso from the Samana Peninsula, and L. asbolepis from the Sierra Martin Garcia, Dominican Republic, and L. leptepileptus from the Massif de la Selle, Haiti. These three species together with L. bilineatus and L. pyrites form a distinct group of Leptotyphlops that is restricted to the West Indies. All five species are compared and a key to the seven species of the genus known from the West Indies is presented. The first collection of a leptotyphlopid from Hispaniola (Thomas 1965) resulted in increased field effort to secure additional specimens of these secretive snakes. Further collecting yielded species of this genus different from Leptotyphlops pyrites Thomas from three widely scattered points on the island (Fig. 1): The Samana Peninsula and the Sierra Martin Garcia in the Dominican Republic and the north slopes of the La Selle Massif in Haiti. The snakes from each of these localities not only are distinct from L. pyrites but also from one another. Field work during the past few years also has extended the known range of L. pyrites from the vicinity of the type-locality near Pedernales, Dominican Republic, west into Haiti along the south coast and north into the Valle de Neiba. Thomas (1965) considered Leptotyphlops bilineatus Schlegel of the Lesser An-tilles and L. pyrites to be the only known members of a distinct Antillean group. The defining feature of this "bilineatus group" was the presence of two subocular supralabial scales that prevent the ocular scale from extending to the labial margin. In all other members of the family, a single scale called the oculolabial (ocular of Klauber 1940) covers the eye and extends to the labial border. The two original species in the group also had a similarly striped color pattern. The three new species described herein are members of the bilineatus group that depart signif-icantly in certain features from L. bilineatus and L. pyrites. We continue to use the term "bilineatus group" as a convenient means of designating those species of Leptotyphlops having the subocular supralabial scales. That all of the known members are restricted to the West Indies suggests that we may be dealing with a monophyletic radiation. However, it is also possible that the group is non-monophyletic and represents remnants of an old, formerly more widespread group within the genus, whose only relicts happen to be West Indian. Following this interpretation, the presence of subocular supralabial scales could well be a plesiomorphous character. An osteological study under way (Thomas) may clarify relationships within the genus and shed light on the nature of the bilineatus group. Methods and Terminology We use certain conventions of description and measurement that should be noted.