400 HYMENOPTEKA. 



5. Brachycistis sciron. 



Long, fere 14 millim. J . 



Hab. Mexico, Northern Sonora (Morrison). 



The head black, the mouth and mandibles piceous, their apices blackish ; shining, 



impunctate, sparsely covered with long, pale, fuscous hair ; behind the eyes the head is 



rounded and not half their length there ; the ocelli not much raised, surrounded by a 



depression, a straight indistinct furrow uniting the posterior pair. The antennae 



reach to near the middle of the second abdominal segment ; the scape has a few white 



hairs ; the flagellum is almost glabrous ; the third joint is longer than the basal two 



joints united ; the third and fourth joints are subequal. The thorax is sparsely covered 



with long white hair ; the pronotum is closely punctured ; the mesonotum is blackish 



in front in the centre, and is shining and impunctate. The scutellum is very shining, 



impunctate, covered with long white hair: the furrow at its base is wide and deep. 



The median segment is covered with long white hair ; the apex has a rather abrupt 



slope, rounded at the top ; the base is shagreened ; in the centre at the base are two 



narrow keels, converging towards the apex, and outside these is an indistinct keel. 



The pleurae are covered with long, soft, white hair. The pro- and mesopleurse are 



somewhat strongly punctured to near the apex, except the latter behind. The sternum 



is impunctate. The metapleurae are impunctate, except at the apex ; there is an oblique- 



not very distinct depression at the base, narrowed towards the apex, and reaching a 



little beyond the middle of the segment. The abdomen is distinctly longer than the 



head and thorax united, shining, impunctate, covered with long, soft, plae yellowish 



hair. The petiole is longer than the second segment, much narrowed at the base, 



gradually dilated towards the apex ; beneath, it is shagreened, the sides with a few 



punctures, and down the centre towards the apex are two indistinct keels. The 



other dorsal segments are shining and impunctate ; covered, but not thickly, and 



especially towards the apices, with long pale hair. The apical half of the terminal 



segment is somewhat coarsely punctured, margined, and slightly depressed. The legs 



are coloured like the thorax, except that the anterior pair are paler and more yellowish 



in tint ; covered with long white hair ; the apices of the hinder tarsal joints fuscous. 



The wings reach near to the apex of the abdomen, clear hyaline ; the stigma deep 



black, paler at the extreme apex ; the nervures fuscous, paler towards the apex. The 



radial cellule is wide, shorter than the stigma, originating a little beyond the middle 



of it ; the basal and apical abscissae oblique. The first transverse cubital nervure is 



curved towards the base, the third towards the top ; the first recurrent nervure is 



received at the base a little more than the length of the second cubital cellule at the 



top ; the second recurrent nervure is received very shortly beyond the middle of the 



cellule. The cubital nervure does not extend beyond the apex of the third cubital 



cellule. 



