166 BULLETIN 160, UNITED STATES NATIONAL MUSEUM 



This combination has not been exactly matched in the series of H. 

 eximia available for study. The tarsal fold on immature individuals 

 of eximia is occasionally indistinct and when viewed under a micro- 

 scope can be detected only by utilizing the light to the best advantage. 

 A distinct tarsal fold was observed in a representative series of 

 eximia from Vera Cruz, Guanajuato, Nayarit, and Michoacan, and in 

 at least 13 of these 35 specimens this tarsal fold was distinctly sharp- 

 edged. The tarsal fold extends in a somewhat curved line from the 

 inner metatarsal tubercle nearly to the tibio-tarsal joint. 



Individual variation in a tree frog as widely distributed as H. 

 eximia occasions no surprise. In this species the dark markings on 

 the upperparts generally run more to longitudinal dark streaks than 

 to distinct dorsal spots. A specimen taken at Ciudad in Durango 

 (U.S.N.M. No. 14083), however, has an unusual color pattern, con- 

 sisting of closely spaced dark spots and streaks that extend from tip 

 of snout to vent. Another specimen taken at Oaxaca in Oaxaca 

 (U.S.N.M. No. 47908) has a large inner and a minute outer meta- 

 tarsal tubercle. In at least one specimen, labeled as coming from 

 Guanajuato (U.S.N.M. No. 9898), the tibio-tarsal joint reaches only 

 to the tympanum. 



It is often possible to point out pecularities that seem to be diag- 

 nostic characters in a limited series, but such distinctions frequently 

 disappear when a large number is available. While the extreme 

 variants of H. eximia may seem quite distinct, and this variability 

 may account in part for several of the synonyms, there are so many 

 intermediate types of color pattern that differences of this sort can 

 hardly be considered of diagnostic importance. The average indi- 

 vidual of eximia has a black spot on each upper eyelid; paired longi- 

 tudinal dark streaks on back; dark spots in sacral region; a lateral 

 dark streak, edged above with white, from nostril to eye, and from 

 posterior edge of upper eyelid through tympanum and along sides to 

 about level of middle of sacrum; and a white or light-colored stripe 

 along upper lip below eye from end of snout to axilla. On some of the 

 specimens, the color pattern of the upperparts consists of scattered 

 dark spots, without any tendency toward uninterrupted streaks. 

 Many specimens have a pair of longitudinal sacral streaks. A few 

 specimens were noted that have uniformly colored upperparts without 

 any trace of dorsal dark spots. A peculiarly marked specimen from 

 Nayarit (U.S.N.M. No. 65890) had longitudinal dark streaks and also 

 numerous fine black specks on upper surface of fore and hind limbs, 

 and a lesser number on sides and back. A few individuals have com- 

 plete transverse dark bars on upper surfaces of hind limbs, while 

 others have dark spots, but no complete crossbars. At least 10 

 specimens having a light-edged dark streak along outer surface of 

 tibia were noted. The hinder surface of the thigh occasionally 

 exhibits a distinct color pattern consisting of a darker area more or 



