248 BRITISH ICHNEUMONS. [Svzaic/iis. 



SYZEUCTUS, Forstev. 



Forst. Verb. pr. Rheinl. 1868, p. 167. 



Metathoracic spiracles large and elongate ; metapleurae not discreted 

 throughout from the metanotum by a carina. Areolet elongately petio- 

 late ; nervellus intercepting below centre ; face more or less intumescent ; 

 notauli entirely wanting ; scutellum laterally margined at the base only ; 

 basal abdominal segment glabrous with spiracles before its centre ; tarsal 

 claws shortly dentate and elongately setiferous. Thorax and abdomen 

 rarely red, but usually very profusely flavous, marked; scutellum and post- 

 scutellum often entirely flavous. Frons sometimes bituberculate. 



This genus has hitherto formed part of Lissom/a in our British lists and 

 in its general facies there is little distinction, but the large and elongate 

 metathoracic spiracles are, I think, sufficient to warrant generic rank, to 

 which its species were first raised by Thomson, under the name Syzcticfa. 

 The colouration of two of the British species is sufficient to superficially 

 distinguish them from all our Lissono/ac, of which the only kind with pale 

 postscutellum has the abdomen mainly red ; in the third the two acute 

 frontal horns will at once distinguish it from all our other Lissouo/idcs. 



None of our species appear common, in fact two are very doubtfully 

 indigenous ; of the remaining eight palaearctic species of this genus, all 

 hut Lissono/a apica/ts, Gra.\: { = L. peiiolaris, GrdiV.) have been described 

 since i888, and are of infrequent occurrence on the Continent ; nor have 

 they been bred. 



As in the case of G[yp/a, I do not consider that the possession of a pair 

 of small frontal tubercles, even when combined with traces of an apical 

 metapleural carina, is sufficient to warrant the erection of a distinct genus 

 {Dicemtops, Forst.) for the reception of Lissonota hicornis. The shape and 

 size of the metathoracic spiracles has been found to be a good and natural 

 character, since first enunciated by Wesmael in 1844, but small capital 

 excrescences cannot, I think, be so regarded. 



Tabic of Species. 



(4). I. Frons mutic ; abdomen not red. 



(3). 2. Petiolar area carinate ; central seg- 

 ments elongate ; wings apically 

 infumate .. .. .. .. i. 'swqvi.xxokwa. Fab. 



(2). 3. Petiolar area wanting ; central seg- 

 ments transverse ; wings hardly 

 infumate .. .. .. ..2. irrisorius, t^ojj-/. 



(i). 4. Frons with two distinct horns; abdo- 

 men mainly red .. .. ••3- HICORNIS, Grav. 



