Elaterid beetle larvae. Pyrearinus termitilluminans (sp .n., Costa, 1982.) Over twenty functions of bioluminescence have been advanced (Buck, 1978). Prey attraction has been suggested as a probable cause for luminescence in only two cases, benthic fishes (refs. in Buck, 1978) and fungus gnats (refs . in Lloyd, 1978; Sivinski, in press). This study reports an additional example of prey attraction in a Neotropical elaterid beetle larva, pyrearinus termitilluminans.As early as 1850 travelers to central Brazil have reported termite mounds with "pale glows of phosphorescent light, like coals in the ashes" (Smith, 1879; Castelnau in Branner, 1909). Various explanations were offered for these mysterious lights, from fungus and bacteria to the termite mounds themselves (Knab, 1909;Neiva & Penna, 1916; Branner, 1909) . Harvey (1952), in his comprehensive review of bioluminescence suggested that the lights might emanate from an insect living in or collecting on the termite hills, singling out glowworms, fireflies and dipterous larvae as possible candidates. I recently found that these lights were produced by the larvae of an undescribed species of pyrearinus. Costa (1982) named the new species termitilluminans.The author recently found in Mathews (1977: 51) reference to :\ similar form of bioluminescence from unidentified Elaterid larvae living in the gallery forest mounds of Cornitermes bequaerti. An explanation similar to the one advanced in this paper was offered by Mathews.
METHODS AND RESULTSIn 1980 and 1981, in Emas National Park in the western region of Goills State, Brazil, the phenomenon of bioluminescent termite mounds was observed. Pyrearinus larvae in general are similar to those of all Pyrophorini, differing mainly in the way they luminesce (Costa, 1978). However, P. termitilluminans larvae are very different than other pyrearinus larvae so far examined (Costa, pers. comm.). Larvae obtained from two termite mounds have an average length of 17.9 mm (S. D . = 5 .0; N = 180) and ranged