Rhjssa.] BRITISH ICHNEUMONS. 25 



mesonotum closely and regularly trans-striate throughout, with notauli 

 entire and often deeply impressed ; metanotum longitudinally canaliculate, 

 areola rarely indicated ; spiracles oblong or oval. Scutellum subconvex 

 and apically obtuse. Abdomen cylindrical, sessile, smooth and shining, 

 glabrous or obsoletely alutaceous ; J with the ventral valvulae exserted; 

 9 with the anus subcompressed, the third segment not basally impressed, 

 the eighth exserted and subtriangular, the apical ventral not reaching 

 base of terebra, which is longer than the body with the sheaths not pilose. 

 Legs, especially the hind pair, elongate ; tarsal claws simple ; posterior 

 coxae subcylindrical. Wings ample, though not broad, with the areolet 

 triangular, sessile or petiolate ; the nervures disposed as are those of 

 Coli'ocentrus. 



This very distinct genus may be known by the transversely rugose 

 thorax, somewhat relating it to Xorida, between which and Coleocefitrus 

 it would appear, as is pointed out by Thomson (O.E. 737), to form a 

 transitional group of species. Holmgren split off those species of Rhjssa 

 possessing no central clypeal tooth and having the abdomen entirely 

 glabrous, creating for their reception the genus l^hahssa (Ofv. 1859, 

 p. 122). Since we possess but three of Gravenhorst's species and the two, 

 which fall into Thalessa, are in need of confirmation as indigenous, it 

 appears advisable to group them together, especially since the features of 

 Holmgren's genus, which is synonymous with jMegar/iyssa, Ashmead 

 (Canadian Entom. 1900, p. 3O8 ; mr Adams), are of so unimportant a 

 character. 



'I'able of Species. 



(2). I. Clypeus centrally produced ; seg- 

 ments not emarginate (RhyssA, 

 aiictt.) .. ..I. PERSUASORIA, Zz«;i!. 



(i). 2. Clypeus truncate; central segments 

 apically emarginate (ThalessA, 

 Holnigr.) 



(4). 3. Scutellum and abdomen white- 

 marked; areolet sessile ..2. LEUCOGRAPHA, Grav. 



(3). 4. Scutellum and abdomen black ; 



areolet petiolate . . . . . . 4. curvipes, Grav. 



1. persuasoria, Linn, 



Ichneumon pcrsuasorius, Linn. F. S. 400; Geer. Mem. I. pi. xxxvi, fig. 7 ; 

 Panz. F. G. xix. 18; Don. B. I. xv. 522, ? . Pinipla persuasoria, Fab. I'iez. 112. 

 Rhyssa persuasoria, Gr. I. E. iii. 267 ; Ste. 111. M. vii. Suppl. p. 2, pi. xxxix, fig. 1. 

 S ; Ratz. Ichn. d. Forst. i. 121, pi i, fig. 22 ; Holmgr. Sv. Ak. Handl. 1860, n. 10, 

 p. 9 ; Tasch. Zeits. Ges. Nat. 1863. p. 251 ; Voll. Pinac. pi. xi. fig. 5 et 6, j ? . 



Head laterally intumescent and as broad as the eyes, frons and face 

 subglabrous ; epistoma deplanate, clypeus narrow and centrally obtusely 

 produced ; palpi and all the orbits more or less white, though sometimes 

 immaculate vertically ; J with the face also entirely white. Antennae 

 filiform, shorter than the body, scape black ; flagellum generally dull fer- 

 rugineous beneath or even entirely, with the joints elongate, apically 

 nodulose and the basal one distinctly curved. Thorax subcylindrical, 

 black ; metanotum centrally canaliculate ; propleural marks, pronotum 

 broadly in front, a line before and a callosity beneath the radix, a mark 

 above the intermediate coxae and another above the hind ones, which 



