324 BRITISH ICHNEUMONS. [Megaplectes. 



in July ; the only subsequent mention I can find is that of Desvignes' 

 specimens. It has been bred in Germany from Clostera anachoreia, and 

 in Sweden it occurs in late autumn ; indeed it does not appear to emerge 

 on the Continent, where it is widely distributed throughout the northern 

 and central districts, until the end of September and October, and even 

 then to be very rarely met with, which may account for the time elapsed 

 since it has been noticed with us. 



ACRORICNUS, Ratzeburg. 



Ratz. Ichn. d. Forst. iii. (1852), 92 ; Linoceras, Tasch. Zeits. Ges. Nat. 1865, p. 105. 



Head narrowed anteriorly, vertex declived ; eyes strongly convex, 

 internally sub-emarginate above antennae ; face deplanate and narrowed 

 towards mouth ; frons smooth, with scrobes obsolete ; labrum free ; 

 clypeus sub-deflexed, apically truncate and only laterally discreted ; man- 

 dibles somewhat narrowed apically, with the upper tooth the longer ; 

 genal costa nearly contiguous with the oral. Antennae with f^agellum 

 filiform, basally sub-attenuate and, in $ , cylindrical, with the joints not 

 apically incrassate ; scape short, sub-globose, slightly excised. Pronotum 

 short ; epomiae distinct, transverse, abbreviated above ; mesonotum 

 hardly declived anteriorly, notauli extendmg beyond its centre ; meso- 

 sternum with lateral sulci entire, inflexed ; metathorax short, costae 

 distinct ; spiracles large and linear. Scutellum gibbous. Abdomen 

 elongate-fusiform, compressed ; basal segment filiform, of equal breadth 

 throughout, curved and very smooth, with spiracles only just behind 

 centre ; second segment with spiracles behind centre and thyridii some 

 distance from base ; terebra reflexed. Legs slender ; anterior tibiae 

 obsoletely spinulose, the front ones not inflated ; calcaria elongate ; fifth 

 tarsal joint as long as third. Upper wings with the internal cubital 

 nervure a little curved, its nervelet wanting ; areolet large, emitting re- 

 current nervure from its centre, its sides hardly convergent above ; cubital 

 nervure emitted from centre of second discoidal cell. Hind wings with 

 median and posterior nervures complete to apex ; the humeral elongate 

 and somewhat curved ; nervellus post-furcal and intercepted nearly in the 

 centre. 



Acroricnus macrobatus 

 A. macrobatus, <S (after Ratzeburg). metathorax. 



This genus will at once be recognized by the filiform petiole, smaller 

 lower mandibular tooth and curved internal cubital nervure. Four other 

 palaearctic species are known, none of which are likely to occur in Britain. 



