3 28 [3xme, 



nearly allied to that species, although I place it in a different section. 

 The flanks of the elytra are certainly a little visible, but, as I explain 

 below, this character is too slight and uncertain in several species to be 

 relied on. 



[^HelopJwrus aeneipennis. In some individuals of this protean 

 species the flanks of the elytra are distinctly visible, so that we mention 

 it here, though we place it in the next section, q.v.]. 



h". Flank of elytra not (or very slightly) visible beneath.* 

 This character, though an important one, is very ditHcult of appli- 

 cation, because there are several species that would be as well placed in 

 one group as in the other. A glance at tig. 7 ! , flank visible, and fig. 72, 

 flank not visible, will make this comprehensible without further 

 explanation. 



28. — Helophorus aeneipennis Thorns. 



This species, which in Britain is the most abundant of the genus, 

 is so variable in colour, sculpture, size and shape, as to be very difficult 

 to diagnose. Even the aedeagus varies considerably, but always is 

 elongate, with a long basal piece, and usually is much infuscate 

 (fig. 45). The colour is always dark, the elytra being strongly 

 infuscate, or even black, the legs rather sordid yellow,' the bases of the 

 femora often blackened, and the club of the antennae obscured, or even 

 blackish ; the sides of the thorax only slightly or not at all yellow. 

 The elytra are usually elongate, and are slightly impressed in front of 

 the middle, but sometimes this depression is nearly absent. The thorax 

 varies in sculpture ; the submedian grooves are usually but little 

 angulate, and the median intervals are either nearly smooth or are 

 granulate. The punctures on the elytra are moderately coarse, and are 

 very close together in longitudinal sequence, the interstices are never 

 in the least carinate ; the epipleuron is rather narrow and nearly always 

 strongly infuscate, the flanks usually not visible, though in some 

 specimens they may be slightly seen. 

 Length 3-4^ mm. 



This species and H. walkeri are so variable, and some of the 

 specimens so closely approximate, that it is not a matter for surprise 

 that they are mixed in collections, and I should have treated them as one, 

 except that the aedeagus indicates that they are really segregated, and 

 I find that after becoming acquainted with the variation I can always 

 say previous to dissection what the aedeagus will prove to be. Some 

 of the females are certainly very difficult to identify. 



* Cj'. ante^, Vol. li, p. 274. 



