Lesser Searcher Beetle Calosoma inquisitor
Strong, black ot metallic dark bronze beetle measuring 16 to 22 mm. There are green or purple reflections at the edges of elytra and pronotum. The elytra have 15 lines, with very small dots inside. Further more there are setiferous punctures. It's nephew, the very rare Forest Caterpillar Hunter (Calosoma sycophanta)is about 6 mm bigger and metallic green.
The adult beetles are capable flyers and may be seen hunting for caterpillars in shrubs and bushes, but also high up in trees. The caterpillars of the Oak Processionary are among its most beloved food, which is fortunate for people, for the caterpillars of this moth have few natural enemies. Also the caterpillars of Tortrixes are appreciated. The larvae hunt underground for pupae mainly. They pupate underground and new beetles emerge in June. They stay underground motionless (in diapauze) untill next spring.
The numbers of Lesser Searcher Beetles fluctuate. In some years it may be a common species, but very rare the next two or three years. In general it is an uncommon species all over Britain and Ireland, except for Northern Scotland.
The Lesser Searcher Beetle is also known as the Caterpillar-hunter