Homocidus | BRITISH ICHNEUMONS. 113 

subhamate marks; mesosternum laterally nitidulous and sparsely punc- 
tulate below, immaculate in both sexes; metathorax rugose-punctate, 
dull with the areae indicated. Scutellum immaculate black. Abdomen 
half as long again as the thorax with the central segments red, and fifth 
to seventh laterally concolorous beneath ; first segment finely scabriculous 
with short basal carinae; postpetiole quadrate ; second slightly transverse 
and smooth, with its base finely rugulose between the thyridii ; third to 
seventh segments of 2 becoming gradually more strongly compressed to 
anus. Legs not very stout, pale fulvous; trochanters and anterior coxae 
pale testaceous ; hind tarsi with claws and ungues somewhat elongate. 
Wings hyaline ; stigma pale testaceous; apical abscissa of radial nervure 
a little longer than the basal ; areolet small and sessile ; nervellus inter- 
cepted in its centre. Length, 4—54 mm. 
The areolet is rarely wanting and the scape sometimes subimmaculate 
beneath. 
This species is very similar to Zoofrephus from which the obsolete 
notauli will at once distinguish both sexes, and its strongly compressed 
abdomen the female; it may easily be mistaken for Promethus sulcator, 
especially in the Q abdominal conformation, but the facial sculpture is 
entirely different. 
It occurs from Lapland to Prussia, where it was “aus Sy7phus-Tonn- 
chen erzogen” by Brischke; and is probably common in Scotland, 
though I have no records thence. Waterston, however, took several in 
St. Kilda in July, 1907; and it is reported from Blackburn (Bowdler) ; 
Tarrington, in Hereford (Yerbury); Tresswell, in Notts. (Thornley) ; 
Lastingham in Yorks and St. Albans (Marshall); Brundall, Eaton and 
Mousehold, near Norwich (Bridgman); Tostock, in Suffolk (Tuck) ; 
Felden, in Herts. (Piffard); and Rossbeigh, in Kerry (Bouskell). To the 
south of the Thames it appears to be much rarer; I have not seen it in 
the Isle of Wight, nor Marquand at Lands End; Bignell took one at 
Longbridge, near Plymouth; Wilson Saunders found it at Wimbledon; 
Champion at Esher; and Capron only four at Shere in Surrey. I have 
seen it from the banks of the Humber, in the Hull Museum; as well asat 
Peterborough, in Northants, and Wroxham and Winterton in the Norfolk 
Broads. It is very abundant in marshy places, especially on the coast in 
August and September, though it first appears in the first week of June 
and also occurs in dryer situations, never on flowers but usually by sweep- 
ing low herbage, especially water mint (J/entha hirsuta), sometimes long 
after dark. The strongest evidence I possess for considering it distinct 
from the next species is that it was abundant at Southwold in September, 
1907, when not one of the latter occurred with it. It is abundant through- 
out Suffolk at Easton and Covehithe Broads on the coast, Henham, 
Brandon, Freston, Claydon, Monks’ Soham, Tuddenham Fen, Herrings- 
well Fen, and Pakenham Fen. 
29. hygrobius, Thoms. 
Bassus festivus, Holmgr. Sv. Ak, Handl. 1854, p.84; Wb. cit. 1855, p. 368 ; 
Brisch. Schr. Ges. Konig. 1871, p. 106, ¢ @ (mec Fab.). Homoporus hygrobius, 
Thoms. O. E. xiv. 1524; Morl. Trans. Ent. Soc. 1905, p. 429, ¢ 2. 
A black species with flagellum ferrugineous, epistoma and mouth and 
humeral marks pale testaceous, abdomen more or less narrowly in the 
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