A new species of Stethelmis Hinton (Coleoptera: Elmidae) from Argentina and description of its larva

Description of the putative mature larva of the Neotropical genus Stenhelmoides Grouvelle (Coleoptera: Elmidae)

Stenhelmoides Grouvelle is a Neotropical genus of Elmidae and although it exhibits a wide distribution, until now no larvae had been associated with adults of this genus. Larvae, very likely belonging to this genus, were associated based on co-occurrence with adults. Eleven larvae and nine adults were examined from ten localities at altitudes between 30 and 682 m a.s.l. in the Andean, Caribbean and Pacific regions in Colombia. Mature larvae of the Stenhelmoides rufulus (Hinton) are described and illustrated for the first time. A larval diagnosis for the genus is presented; body shape, distribution and form of setae and number of pleural sclerites are diagnostic characters for larvae of this genus. Comparative notes with similar larvae of other Elmidae genera are presented. The existing generic keys are updated to include larvae of Stenhelmoides. Comments on distribution and habitat of Stenhelmoides larvae are also provided. This work contributes to enhance the knowledge of Neotropical larvae, which have been described for only approximately 56% of genera and 8% of species of Elmidae.