Heterogyna and l^ossorial Hi/menojJtera. 219 



(2) 1. ^ antennre 12-jointed ; 2 ^"^ ? 11-jointed . . acervorum. 

 (1) 2. ^ antennte 13-jointeil ; J and ^ 12-jointed. 



(4) 3. (J thorax in front of the converging lines very 

 finely rugose : club of the antennae in J and ^ 

 dark . . . . . . . . . . . . . . unifasciatus. 



(3) 4. (J tliorax in front of the converging lines smooth 



and polished ; club of the antenna! in 5 and ^ 



pale , . . . . . . . . . . . . . Nylanderi. 



1. acervorum, Fab. Ent. Syst. ii. p. 358. 



3^ black ; mandibles and le.cjs brown, joints and 

 tarsi paler ; clothed with long whitish hairs, especially 

 on the dull, rugose head ; mandibles not toothed ; antennfe 

 12-jointed, scape very short and thick, about as long as 

 the second joint of the flagellum, which is much longer 

 than the first ; thorax irregularly rugose posteriorly ; 

 metatliorax tuberculated at the sides behind ; nodes of 

 the petiole smooth and shining ; abdomen shining and 

 smooth ; wings very thin, milky white. Length 5 mill. 



$ brownish red ; head, thorax, and abdomen above, 

 nearly black ; mandibles, scape, and legs paler ; an- 

 tennae 11-jointed, head finely and longitudinally rugose ; 

 tliorax and nodes of the petiole also rugose ; metatliorax 

 with two stout, rather blunt spines ; abdomen shining, 

 with scattered white hairs ; legs with prominent hairs. 

 Length 4 — 5 mill. 



^ testaceous-red ; head, apex of antennEe, and abdo- 

 men nearly black ; thorax sometimes with a more or 

 less extended dark patch on the disc. Entire insect 

 clothed with scattered short, upright, pale hairs ; head 

 and thorax rugose ; antennae 12-jointed ; metatliorax 

 with two short, rather blunt spines ; first joint of the 

 petiole nearly quadrangular looked at from above, from 

 a side view much raised posteriorly ; both joints more 

 or less rugose ; abdomen smooth and shining. Length 

 4 mill. 



Hah. — Under bark, &c. ; chiefly a northern species. I 

 have taken it, however, near Croydon, and it occurs, I 

 believe, in other localities near London. 



2. Nylanderi, Foerst. Hym. Stud. Form. p. 53. 



(? brown ; the mandibles, antennae, and legs pale ; 

 mandibles 4- or 5-tootlied ; scape of the antennse as 

 long as the first three or four joints of the flagellum ; the 

 first seven joints of the flagellum are of about equal 



TRANS. ENT. SOC. 1880. — PAKT IV. (DEC.) X 



