Ovipositing Chrysotoxum

31st May 2011, Tuesday

This Chrysotoxum female was ovipositing on the leaves of a Montbretia plant in my garden this afternoon. The eggs ( or egg packages ) were left in groups of two or three spaced out along a number of leaves. This species could be C. cautum or C. veralli………..are the thoracic dorsum hairs ”long & dense”  ( C. cautum ) or ” shorter” ( C. verralli) ?. Ball & Morris say the larva of C. cautum are unknown, but thought to be associated with ants. Pupae of C. verralli have been found under a stone, and females seen ovipositing close to ant nests. There is an ants nest four to five feet away from the plant in the picture. Colin Boyd by email.