Key to Delia males with bipartite sternite III

Four species within the Delia cardui species group are presently known to have a bipartite male sternite III. The species can be identified in the male sex by the following key.

1 Sternites III and IV both much wider than sternite V (Figs. 4–5) ............................................................ 2

- Only sternite III wider than sternite V ......................................................................... D. polaris Griffiths

2(1) Sternite III with short setae only (Fig. 5).................................................................................................. 3

- Sternite III with several long setae reaching beyond sternite V (Fig. 4) .................................................... ................................................................................................................................ D. rimiventris sp. nov.

3(2) Tergite III on ventro-flexed lateral hind margins with some very long setae reaching beyond tip of abdo- men .................................................................................................................................. D. bipartita Suwa

- Tergite III without long setae on lateral hind margins ......................................... D. bipartitoides sp. nov.