Polistichus connexus (Geoffroy in Fourcroy, 1785)
Fowler (1887) writes of this species: ‘Clay banks on the coast, also further inland at the foot of posts, under stones and clods, in flood refuse etc... Generally distributed - from Sussex, occasionally common... in profusion by digging about posts at Queensboro’. This suggests that perhaps it was not so unusual for collectors to find the species in the right area. Nowadays this is a very local species in the UK which has long been considered to be in decline and vulnerable, however there are many records from light traps across the south of England from 2019 and 2020, mostly recognized from postings on Facebook, that suggest it has either been generally overlooked or has increased greatly in range and abundance in recent years. Until this recent expansion it occurred from Dorset to east Kent and north Essex and was generally coastal although it occasionally appeared inland, and sometimes far from the coast. There is a record from 1939 from Windsor Forest and in August 1990 a specimen was recorded at an MV light sited among grassland and heather on acidic soil near a gravel pit on the southwest part of Wimbledon Common. Another specimen was recorded from the London area in 1991. Before the many postings on Facebook the most recent records were from only 4 vice-counties from southeast England. Typical habitats are cliff bases near fresh water, on clay soil near rivers, at roots of trees and in damp places on sandy heaths. Adults occur from April to October and the species is thought to be a spring and/or summer breeder. They may be abundant where found. On the continent they appear earlier in the year with increasing latitude. The species is a good flier and is most readily recorded at MV light, in recent years often from gardens and other ruderal sites. Other forms of trapping are usually disappointing. They occur in river valleys and areas with networks of small streams and are sometimes found in numbers in flood refuse, in these habitats they are rarely recorded in numbers but they may be common at light and arrive over a long spring and summer season.
The elongate form, distinctive colouration and shape of the pronotum makes Polistichus distinct among the U.K. fauna. 8-9.5mm. Elongate and depressed with long erect or semi erect pubescence throughout. Head and pronotum brown with appendages lighter. Head flat with large sparse punctures and lacking microsculpture (x30). Eyes very prominent and transverse (side view) with strongly contracted temples behind forming a short neck. Mandibles produced forward and sharp. Terminal segment of all palps cylindrical. Antennae entirely pubescent, basal segment long and broad, second segment small and the remainder elongate. Pubescence behind eyes long and curved forward. Pronotum quadrate or slightly transverse, with large punctures and deep, wide basal fovea. Lateral margin constricted towards base and strongly edged. Hind angles obtuse and sharp. Scutellum triangular and densely punctured. Elytra distinctly coloured; margins black, disc with a longitudinal red mark to the shoulder. Each with 7 strongly punctured striae complete almost to the apex. Without an abbreviated scutellar stria. Interstices finely punctured throughout. Side margins slightly explanate and with irregularly spaced very large punctures. Apex truncate and evenly curved, with a fine membrane beyond the margin. Apical abdominal tergites visible beyond the apex. Fore tibia with a very deep antennal cleaner. Meso- and meta-tibiae with 2 spurs at apex. Claws smooth. Wings fully developed. Male protarsi with basal segments dilated.
Polistichus Bonelli, 1810
This is a small genus including 2 European species. Polistichus connexus (Fourcroy, 1785) is widespread from Spain, including the Azores, and Tunisia east to Ukraine, Kazakhstan, Uzbekistan and northwest Siberia although it is much more common in the southern parts of its range. It is the only member of the tribe to occur in the U.K. P. fasciolatus (P. Rossi, 1790), sometimes considered to be a subspecies of P. connexus, is similarly widespread. A third species, P. inornatus Gestro, 1881, is listed in World Carabidae but we have not been able to trace this and Fowler (1887) mentions a third species from Central Asia but does not name it. P. hopei Oustalet, 1874, is known only from lower Oligocene (28.4-23.03 Ma) fossils at Aix-en-Provence, France. The genus is characterized by the large pubescent basal antennal segment and the membranous elytral apex. The tarsal segments are not bilobed.