Hemerodromia Seguyi, nouvel empidide d'Algérie destructeur de simulies

Résumé

Dans une précédente note ont été étudiés les premiers stades d'un Empidide d'Algérie, de la sous-famille des Atalantinae, Roederella ouedorum, dont les larves, rhéophiles, détruisent les larves et surtout les nymphes de Simulium sp. Un autre Empidide d'Algérie, de la sous-famille des Hemerodromiinae, Hemerodromia seguyi, dont la larve, la nymphe et l'imago sont décrites ici, a un mode de vie tout à fait analogue; sa larve vit au sein des colonies de larves de Simulies; ces dernières sont capturées et sucées par la larve prédatrice. La nymphe d'Hemerodromia seguyi est nue et fixée sous des pierres immergées, dans des zônes de courant faible.

Summary

In a swift stream of the Aures mountains (Algeria), were collected, on April 1950, a large number of larvae of an Empidid fly of the subfamily Hemerodromiinae: Hemerodromia (Metachela) seguyi n. sp.; they live on immerged rocks, among larvae of Simulium sp., upon which they prey; when feeding, the Empidid larva buries its head in its prey and sucks up the flesh. Pupation takes place usually in crevices of immerged rocks at the water's edge, where the current is slow.

The larva and pupa of H. seguyi have been compared respectively to those of Roederella ouedorum, an Empidid fly belonging to the subfamily Atalantinae. The main differences between the larvae are not furnished by the head structure, but by the number of abdominal prolegs, the disposition of hooks on them and the form of the prominence at the end of the body. Pupae of Hemerodromia are easy to distinguish from pupae of other Empidids, for they have eight pairs of long tracheal filaments; other taxonomic characters are the form of the plates of the head on ventral aspect and the disposition of spines on the abdomen.