Identification key to British and Irish species of Enicospilus

1. Fore wing lacking sclerites in glabrous area of discosubmarginal cell (Fig. 2A); large species, wing length c. 20 mm ................................................................................................................................. 2

– Fore wing with at least one discrete sclerite in discosubmarginal cell (Fig. 2 B–D); smaller species, wing length <15 mm ......................................................................................................................... 3

2. Head posteriorly, in dorsal view, not expanded laterally beyond the eyes; ocelli touching or almost touching eye; antennal socket separated from inner margin of eye by not more than a third socket diameter (Fig. 3A) ................................................................ Enicospilus inflexus (Ratzeburg, 1844)

– Head posteriorly, in dorsal view, expanded so that head is wider than its width at the eyes; ocelli distinctly separated from eye by about 0.2 × diameter of ocellus; antennal socket separated from inner margin of eye by about half socket diameter (Fig. 3B) .............................................................. ....................................................................................... Enicospilus undulatus (Gravenhorst, 1829)

3. Fore wing with distinct, pigmented proximal and central sclerites (Fig. 2B) ................................... 4

– Fore wing with distinct, pigmented proximal sclerite: central sclerite may be present but translucent (Fig. 2 C–D)........................................................................................................................................ 8

4. Pronotum, mesopleuron, mesoscutum and propodeum with dark patches (Fig. 14A)........................ ...................................................................................... Enicospilus combustus (Gravenhorst, 1829)

– Mesosoma lacking dark patches, uniformly testaceous..................................................................... 5

5. Metasoma abruptly tipped with black posteriorly, from 5 th or 6 th tergite (Fig. 14B)........................... ............................................................................................ Enicospilus ramidulus (Linnaeus, 1758)

– Metasoma not abruptly black-tipped (but may be diffusely infuscate ventrally and apically).......... 6

6. Head with temples rounded, more buccate, and with distinct ocular-ocellar space (Fig. 4C); first metasomal tergite in lateral view with better-defined dorsal dip (Fig. 6C); male aedeagus apically paler, apex more rounded, protruding more dorsally and not reflexed ventrally (Fig. 9B)................. ............................................................................................................... Enicospilus myricae sp. nov.

– Head with temples narrowed, straighter, with ocelli adjacent to or only narrowly separated from eyes (Fig. 4 A–B); first metasomal tergite with shallow dorsal dip (Fig. 6 A–B); male aedeagus same colour throughout, apex more smoothly curved, not so protruding dorsally, reflexed ventrally (Fig. 9A) .. 7

7. Temples very strongly narrowed behind eyes (Fig. 4A); scutellum with sides more nearly parallel, heavily punctate and with slight posterior ridge (Fig. 5A); antenna with 51–56 flagellar segments, preapical flagellar segments stouter (Fig. 7B) .......................... Enicospilus cerebrator Aubert, 1966

– Temples less strongly narrowed posteriorly (Fig. 4B); scutellum with sides distinctly converging posteriorly, more sparsely punctate and smoothly curved posteriorly (Fig. 5B); antenna with 58–69 flagellar segments, preapical flagellar segments slenderer (Fig. 7A) .................................................. ....................................................................................... Enicospilus adustus (Haller, 1885) stat. rev.

8. Fore wing with small translucent central sclerite and narrow pigmented distal sclerite (Fig. 2C); fore wing vein cu-a distinctly proximal to Rs&M (Fig. 11A)..................................................................... ....................................................................................... Enicospilus merdarius (Gravenhorst, 1829)

– Fore wing lacking central sclerite and with very faint distal sclerite (Fig. 2D); fore wing vein cu-a opposite vein Rs&M (Fig. 11B)........................................ Enicospilus repentinus (Holmgren, 1860)