20 BULLETIN 18 7, UNITED STATES NATIONAL MUSEUM 



Family LEPTOTYPHLOPIDAE Stejneger 



Leptotyphlopidae Stejnegek, Proc. U. S. Nat. Mus., vol. 14, 1891, p. 501. 

 Type. — Lcptotyfhlops Fitzinger. 



Genus LEPTOTYPHLOPS Fitzinger 



Leptotyphlops Fitzingee, Systema reptilium, 1843, p. 24. — Taylor, Copeia, 1939, 

 No. 1, pp. 1-7, pi. 1 (Mexican species). — Klaurek, Trans. San Diego Soc. Nat. 

 Hist., vol. 9, 1940 (April 30), pp. 87-162, pi. 6, figs. 1-8, maps 1, 2 (United 

 States and northern Mexican species). — Taylor, Univ. Kansas Sci. Bull., 

 vol. 26, 1939 (1940) (Nov. 27), pp. 532-541, figs. 1-5 (key to Western Hemi- 

 sphere species). 



Rena Baird and Gikaed, Catalogue of North American reptiles, 1853, p. 142 

 (type, R. dulcis Baird and Girard). 



Genotype. — Typhlops nigricans Schlegel. 



Range. — Southern United States westward from central Texas, 

 northward as far as Kansas, southward through most of Mexico except 

 the southern central plateau region, Central America, and South 

 America to Argentina ; the Lesser Antilles and Watling Island (Ba- 

 hamas) ; Africa and southwestern Asia. 



Species. — In all, 34 American species and subspecies, 13 of which 

 occur in Mexico ; about 53 in the Eastern Hemisphere. 



KEY TO MEXICAN FORMS OF LEPTOTYPHLOPS " 



1. With supraoculars 2 



Without supraoculars 8 



2. Supraoculars much larger than prefrontal or frontal ; a dorsal pattern 



of dark brown, with distinct longitudinal lines 3 



Supraoculars no larger, or but little larger, than prefrontal or frontal; 

 the dorsal pattern, if dark brown, without distinct longitudinal light 

 lines 4 



3. Rostral contacting supraoculars phenops bakewelli 



Rostral not contacting supraoculars phenops phenops 



4. Twelve scale rows around tail maximus 



Ten scale rows around tail 5 



5. Anterior supralabials entire dulcis 



Each anterior supralabial divided by a vertical suture 6 



6. Parietals not contacting posterior supralabials bressoni 



Parietals contacting posterior supralabials 7 



7. Dorsal scales 224 or more myopicus dissectus 



Dorsal scales fewer than 224 myopicus myopicus 



8. Ten scale rows around the tail 9 



Twelve scale rows around the tail 10 



9. Dorsal scales number 250 or more humilis segregus 



Dorsal scales number less than 250 humilis tenuiculus 



10. Dorsal scales usually less than 260 11 



Dorsal scales usually 260 or more 12 



" Based largely upon Klauber, op. cit., pp. 151-152. 



