Key to chrysidid genera and species of the Nordic and Baltic countries
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How to use the key
Choose an answer to the questions, or move to the next question if the answer is hard to choose. If several answers are available it is also possible to exclude answers.
About this key
The origin of the content in the key to chrysidid genera and Chrysis species of the Nordic and Baltic countries is the paper: Paukkunen J, Berg A, Soon V, Ødegaard F, Rosa P (2015) An illustrated key to the cuckoo wasps (Hymenoptera, Chrysididae) of the Nordic and Baltic countries, with description of a new species. ZooKeys 548: 1–116. doi: 10.3897/zookeys.548.6164.
In order to use the key successfully, specimens should be properly mounted or pinned with both the dorsal and ventral surfaces of the metasoma visible. In the Chrysis ignita and C. fasciata species-groups, the mandibles of both sexes should be opened, genital capsules of males should be extracted and ovipositors of females everted. Colouration of specimens collected with traps containing liquid preservatives, softened using hot water or having been kept in sunlight for a long time, can deviate from the original colouration. Additionally, the colour of fresh and liquid preserved specimens can change when they are dried, most notably greenish shades turn bluish in dry specimens. Geographical variation in colouration is also observed in many species, whereby northern specimens tend to be darker than southern ones.
Distinguishing the sexes of chrysidids can be difficult if the telescope-like ovipositor of the female is not exserted, or the genital capsule of the male has not been extracted. In males, the third metasomal sternite is completely flat and the semitransparent membranous posterior margin of the fourth sternite is usually visible. In females, the third sternite is generally thicker posteriorly and the posterior margin of the fourth sternite is opaque. Additionally, a slender needle-like structure (formed by the first valvulae) can be seen on the tip of the ovipositor in females. This structure is visible even if the ovipositor is not fully exerted.