Revision of the western Palaearctic species of Wesmael (Hymenoptera, Braconidae, Rogadinae). Part 1: Introduction, key to species groups, outlying distinctive species, and revisionary notes on some further species.

Seven new species of the genus Wesmael, 1838 (Braconidae: Rogadinae) are described and illustrated: , , , , , , and A neotype is designated for each of (Nees, 1834) and (Herrich-Schäffer, 1838), and both species are redescribed and illustrated. Hellén, 1927 (not (Curtis, 1834)) is renamed as & , and redescribed and illustrated. Roman, 1917, Wesmael, 1838, and (Noskiewicz, 1956), are re-instated as valid species. A lectotype is designated for Roman. An illustrated key is given to some distinctive species and the residual species groups along which further parts of an entire revision of western Palaearctic species of and will be organised. Biology, host associations and phenology are discussed for the keyed species (in addition to the above, (Herrich-Schäffer, 1838), (Fahringer, 1932), (Thomson, 1892), (Lyle, 1919), (Hartig, 1834), (Kokujev, 1898), (Reinhard, 1863), Wesmael, 1838, (Thunberg, 1822), (Reinhard, 1863), (Herrich- Schäffer, 1838) , (Telenga, 1941), (Thomson, 1892), and (Herrich-Schäffer, 1838)) which are dealt with in full here (with the exception of which is, however, included in the key). The experimental methodology covering the revision as a whole, which involves some behavioural investigation, is outlined.