Lateral dark stripe wide, encompassing entire tympanum; dorsal markings consisting of longitudinal series of flecks or dashes, or of two lines, usually not extending to vent _H. robertmertensi_ 4. Lateral dark stripe indistinct, present only above tympanum and insertion of arm; dorsal markings consisting of narrow lines and dashes, sometimes interconnected; transverse bars on shanks narrow relative to interspaces _H. phlebodes_ Lateral dark stripe absent; dorsal markings consisting of two broad chevron-shaped marks; transverse bars on shanks wide relative to interspaces _H. sartori_ ACCOUNTS OF SPECIES AND SUBSPECIES _Hyla microcephala_ Cope _Diagnosis._--Lateral dark stripe narrow, covering only upper edge of tympanum, bordered above by narrow white stripe; dorsal pattern consisting of pair of longitudinal brown lines and no interorbital bar (eastern populations), or of irregular dark markings forming an X- or )(-shaped mark in scapular region and an interorbital bar (western populations). _Content._--The populations inhabiting the Pacific lowlands of southeastern Costa Rica eastward to Colombia are recognized herein as _Hyla microcephala microcephala_ Cope; the populations in western Costa Rica northward to México are assigned to _Hyla microcephala underwoodi_ Boulenger. _Distribution._--Southern Veracruz and northern Oaxaca southeastward through the Atlantic lowlands of Central America to north-central Nicaragua, thence southeastward on the Pacific lowlands to eastern Panamá, and thence into the Cauca and Magdalena valleys (Caribbean drainage) of Colombia (Fig. 1). [Illustration: Fig. 1. Map showing locality records for _Hyla microcephala_.] Table 1.--Variation in Certain Measurements and Properties in the Hyla microcephala Group. (All Data Based on Adult Males; Mean and Standard Error of Mean Below Observed Range.)