Comparative study of head structures of larvae of Sphindidae and Protocucujidae (Coleoptera : Cucujoidea)

Selected representatives of Cucujoidea, Cleroidea, Tenebrionoidea, Chrysome lidae, and Lymexylidae were examined. External and internal head structures of larvae of Sphindus americanus and Ericmodes spp, are described in detai l. The data were analyzed cladistically. A sister group relationship betwee n Sphindidae and Protocucujidae is suggested by the vertical position of th e labrum. The monophyly of Cucujiformia is supported by the reduced dorsal and anterior tentorial arms, fusion of galea and lacinia, and the presence of tube-like salivary glands. Absence of M. tentoriopraementalis inferior a nd presence of a short prepharyngeal tube are potential synapomorphies of C leroidea, Cucujoidea and Tenebrionoidea. The monophyly of Cleroidea and Cuc ujoidea is suggested by the unusual attachment of the M. tentoriostipitalis to the ventral side of the posterior hypopharynx. Cucujoidea are paraphyle tic. The families Endomychidae, Coccinellidae and Nitidulidae are more clos ely related to the monophyletic Cleroidea, than to other cucujoid groups. S eparation of the posterior tentorial arms from the tentorial bridge and pre sence of a maxillolabial complex are synapomorphic features of Cleroidea an d these cucujoid families. For a reliable reconstruction of cucujoid interr elationships, further characters and taxa need to be studied.