301. 

 CEPHUS FEMORATUS. 



Order . Hymenoptera. Fam. Tenthredinidae Lat. 

 Type of the Genus, Sirex pygmseus Linn. 

 Cephus Lat., Fab., Pz. — Trachelus Jur. — Astatus Klu. — Sirex Linn. 

 Antennce inserted in front of the face between the eyes, rather 

 remote, longer than the thorax, slightly clavate and pubescent, 

 composed of 21 joints, basal joint robust ovate, 2nd subglobose, 

 3rd and 4th long, the following to the 8th decreasing in length, 

 •where they become oblong and are transverse towards the apex, 

 which is ovate (1). 



Labrum minute, concealed beneath the clypeus^ semiorbicular, 

 emarginate, and ciliated with long hairs (2). 

 Mandibles large, crossing before the clypeus, tridentate, pilose 

 externally, with a fascicle of hairs on the inside ; one mandible 

 with the internal tooth very large and spreading (3). 

 MaxillcB terminated by a rather long subovate pilose lobe, fur- 

 nished internally with a long lobe attached by the centre, the 

 superior portion rigid and pilose, the inferior part coriaceous and 

 pubescent. Palpi long, 6-jointed, basal joint short, 2nd a little 

 longer, 3rd longer and the most robust, 4th very long slender 

 and slightly clavate, 5th oval, 6th longer than the 3rd slender 

 and attenuated at both ends (4). 



Mentum long oval and narrowed below the apex, which as well 

 as the base is rigid. Palpi inserted at the anterior angles, as 

 long as the lip, pilose, 4-jointed, basal joint not very long, 2nd 

 rather shorter, 3rd cup-shaped, 4th as long as the 1st subfusi- 

 form, being dilated most towards the base. Labium as long as 

 the mentum composed of 3 lobes, united before the base, pu- 

 bescent at the apex and ciliated with spines, the central lobe 

 being the longest (5). 

 Clypeus broad. Head subglobose, transverse above. Eyes prominent. 

 Ocelli 3 on the crown of the head. Prothorax rather long and nar- 

 rower than the Mesothorax, which with the Scutellum/onHS an oval. 

 Abdomen sessile, rather lung, narrow, cylindric, compressed towards 

 the apex in the females. Ovipositor short and exserted. Superior 

 wings with 2 marginal and 4 submarginal cells. Legs rather slen- 

 der. Tibiae spurred, intermediate toith one, posterior with two spurs 

 towards the middle. Tarsi longer than the tibice, 5-jointed, each 

 joint having a small membranous appendage beneath. Claws long 

 slender and bifid near the apex. Pulvilli distinct (Sf^ hind leg). 



Femoratus Nob. ' 



Black, shining. Palpi testaceous. Head densely pilose. Ab- 

 domen with the membrane at the base subtrigonate and sulphu- 

 reous. Wings very iridescent, costa stigma and nervures pi- 

 ceous. Legs ferruginous ochre, tips of posterior thighs fuscous, 

 middle and posterior tibiae sulphureous at the base, the remain- 

 der in the latter black ; anterior tarsi at the- tips, and the others 

 entirely black. 



Li the Cabinets of the British Museum and the Jlulhor, 



