286 U.S. NATIONAL MUSEUM BULLETIN 2 88 



Color in alcohol. — Dorsal ground color ranging from a moderate 

 brown on top of snout to pale brown on top of head and anterior 

 portion of back to a yellowish on hind part of back and along sides. 

 Entire ventral surface a very pale yellow. Tiny brown spots con- 

 centrated into a rather indistinct transverse blotch above the scapular 

 region and a rounded blotch above the sacral region. Each shank with 

 three distinct but not well-defined transverse bars across their dorsal 

 surfaces. The upper surfaces of all limbs, including thighs, faintly 

 peppered with minute melanophores but with the pale yellow ground 

 color being the most conspicuous element of the pattern. 



Variation. — The type series is rather uniform in structure, but it 

 exhibits a fair amount of variation in dorsal pattern. The dorsal 

 ground color is tan to light brown with a series of dark brown blotches 

 on the back. These blotches range from being asymmetrically arranged 

 to being organized in two somewhat curving, longitudinal rows 

 resembling an hour-glass pattern. There is generally a concentration 

 of pigment on top of the head between the eyes, forming an indistinct 

 to distinct interocular bar. The thighs are nearly immaculate, but 

 the dorsal surfaces of the shanks are generally distinctly crossed by 

 about three blotches of dark brown. 



This is one of the smallest species of Hyla. The holotype, with a head- 

 body length of 20 millimeters, is the largest known specimen. None 

 of the males examined exceeds 18 millimeters in head-body length. 



Remarks. — In using the name "raisera" for this species, Goin and 

 Layne (1958, p. 104) pointed out that their identification was tenta- 

 tive, pending Dr. Juan Rivero's study of the species. Dr. Rivero 

 now informs us that this frog is undoubtedly distinct from H. misera 

 and that it represents an undescribed species. We offered to let 

 Dr. Rivero describe this new species, but since he graciously declined 

 we take this opportunity of dedicating it to him. 



The following life history notes are quoted from Goin and Layne 

 (1958, p. 105) : 



All specimens were collected in wet cutover land and partially flooded meadows. 

 At a distance the call of the male is a delicate, insect-like tinkle, but close at 

 hand it has a more rasping quality. Calling individuals were invariably located 

 above ground, usually at a height of from two to four feet, in a bush or herbaceous 

 plant. In voice and habits, this species is comparable to Hyla ocularis of the 

 southern United States coastal plain. 



Hyla mathiassoni, new species 



Figure 30 



1959. Hyla microcephala. — Stebbins and Hendrickson, 1959, p. 524. 



Holotype. — CNHM 81779, collected at Villavicencio, Meta, Colom- 

 bia, by Phillip Hershkovitz. 



