366 HYMENOPTERA ACULEATA. 



(1894), and a variety, in Orkney (the only form he saw), 

 with pale underside, but even in this variety all the tibiae 

 are clothed with black hairs, otherwise the ? closely re- 

 sembles that of venustus. 



B. venustus, Smith {eognaius, Saund. nee Steph., varia- 

 bilis, Schmied., muscorum, Kirb., senilis, Smith). — This species 

 may be known from the preceding by the pale hairs of the 

 underside and from the following, which it much resembles 

 in some varieties : by its shorter and more even pubescence, 

 and by the darker, somewhat brown hairs of the second 

 abdominal segment, but this darkness is partly, I think, 

 due to the pubescence being more erect than it is in agro- 

 rum, and therefore seen at a different angle ; it also differs 

 from most of the varieties of agrorum in having no black hairs 

 mixed with the pale ones of the abdomen ; pale varieties, how- 

 ever, of agrorum occur without black hairs and dark varieties 

 of venustus ; in the latter case the pubescence of the thorax 

 is partly composed of black hairs, but that of the abdomen, 

 although sometimes, according to Schmiedeknecht, dark 

 brown, is not composed of black and pale hairs intermixed 

 as in agrorum. The only reliable structural characters 

 that I know of, are the shorter, less ragged, pubescence of 

 all the sexes of venustus, the much less produced and rounded 

 posterior margins of the antennal joints in the cJ, their 

 greatest width scarcely equalling half their length, and the 

 form of the armature in which the sagittee are hamate 

 beneath at the apex and not serrate externally, and the wider 

 and more triangular lacinia, whose basal process is produced 

 into an angular point, not into a spine as in agrorum. 



L. 10-18 mm. 



Common in many places and generally distributed. 

 There is no doubt that this is variabilis, Schmied., but 

 Smith's name has the priority. I have re-examined 

 the type of cognatus, Steph., which is in the British 

 Museum. The specimen is very immature, the pubescence 

 being exceedingly pale, and the legs testaceous, the nature 



