86 BRITISH ICHNEUMONS. 



thyridii triangular, small and deeply impressed ; intervening space hardly 

 broader than centre of post-petiole ; terebra obtuse, very shortly exserted. 

 Legs red, coxae and trochanters, as well as apex of hind femora, tibiae and 

 the tarsi blackish ; hind coxae closely punctate, with no scopulae beneath ; 

 front calcaria stout. Wings hyaline ; tegulae in front and radix flavous ; 

 areolet somewhat narrowed above; radius straight. Length, 8-10 mm. 



Wesmael mentions a form of the male with the thorax entirely black, 

 and Gravenhorst's /. microcerus is a form of the female with the pale 

 antennal band hardly visible. 



The characteristic points of this species are the abbreviated antennae, 

 barely reaching to the apex of the thorax, the form of the head, and the 

 structure of the cheeks and mandibles. 



I do not expect this is an uncommon .species in Britain ; it is found in 

 grassy places, and among undergrowth, in June and July. Stephens found 

 it in gardens and houses about London, at Harrietsham, in Kent, in June, 

 1840 (Entom. p. 200), and the form microcerus in Wiltshire; Bridgman 

 took it at Norwich, and Parfitt says it is not common but generally dis- 

 tributed in Devon ; Tuck captured males at Tostock, near Bury St. 

 Edmunds, in June, and Dr. Bailey a female at Pendleton, in 1899. 

 Alderney (Luff) ; Essex (Harwood) ; Darenth, in May (Chitty) ; Copdock, 

 Suffolk, in July (Hocking) ; near Glasgow (Bignell) ; Ripple, near Dover, 

 in August (Sladen). Although it has never been bred, Gravenhorst saw 

 it flying around a colony of Aphides and Syrphid larvae, and it has been 

 several times found on windows indoors. 



2. gemellus, Grav. 



Ichneumon gciiiellus, Gr. I. E. i. 201 ; Ste. 111. M. vii. 147, i ; Wesm Nouv. M^m. 

 Ac. Brux. 1844, p. 33, excl. var. 3 ; Bui. Ac. Brux. 1848, p. 148 ; lib. cit. 1849, 

 p. 36 ; Ilolnigr. Ichn. Suec. i. 131 ; Thonis, Ann. Soc. Fr. 1S88, p. 108 ; Berth. ///;. cit. 

 1S95. p. 226, i ?. Bai-ichneiiinoii gemellus, Thorns. O. E. xviii. i960. Var. /. opticus, 

 Gr. I. E. i. 131 ; Ste. 111. M. vii. 132, i. 



A dark species at once known by its laterally-raised scutellum. Head 

 very little narrowed behind the eyes, cheeks somewhat buccate and apically 

 smooth ; black, mandibles and sides of the apically-emarginate clypeus 

 rufescent ; frontal and vertical orbits pale ; $ also has palpi, labrum, man- 

 dibles, sides of clypeus and of face pale flavous. Antennae black, reddish 

 beneath; of ? sub-filiform with the central joints white above, of c? white- 

 marked beneath scape. Thorax pubescent, narrower than head, of ? 

 entirely black; that of c^ with pronotum and callosities at radix generally 

 pale flavous ; metathorax scabriculously punctate, with complete upper 

 areae, of which the areola is semi-elliptic or semi-lunar, and apically 

 emarginate ; spiracles linear. Scutellum black, short, obtuse, sometimes 

 apically pale-marked ; with raised lateral margins, which extend in $ to its 

 centre, in $ nearly to its apex. Abdomen sub-lanceolate, black, with 

 second and third segments, especially in $ , castaneous and their incisures 

 deeply impressed ; $ has sixth and seventh dorsally white, the seventh 

 alone of $ is very rarely pale-marked ; post-petiole centrally scabriculous 

 or in $ sub-aciculate, laterally indistinctly punctate, carinae distinct and 

 the apical angles obtuse ; second segment with a longitudinal carina on 

 the disc, stronger in $ ; gastrocaeli much broader, deeper and striate in $ , 

 intervening space roughly punctate, as broad as centre of post-petiole. 



