been standing nameless in various collections. I had, myself, after a somewhat cursory 

 examination, referred it to the ants, and bad placed it in the family Poneridae. A few 

 years ago I bad an opportunity of submitting this insect to Dr. Nylander, who thought 

 I was right in so doing, but I must admit he had only time to give it a very slight 

 examination. Prof. Westwood (Tr. Ent. Soc. 1868, p. 329, Pioc. p. xli.) has referred 

 it to the Vespidae, its position being indicated as near the genus Belonogaster, of 

 Saussure. 



" At the lime when the paper was lead, 1 expressed an opinion that it could not 

 belong to the Vespidae : I have therefore felt bound to examine the insect with a greater 

 degree of attention, and have carefully and minutely investigated its structural pecu- 

 liarities : the result has been, that I have changed my opinion as to the family to which 

 it belongs, although I shall still be found to differ widely in that respect from Prof. 

 Westwood, and also from Mr. Haliday, who once examined the insect, and determined 

 that it belonged to the Sphegidce, being in his opinion closely allied to the genus 

 Pelopaeus. 



" Having expressed an opinion that it does not belong to the Vespidae, it is incum- 

 bent upon me to give my reasons. In the first place, all true wasps, the social 

 as well as the solitary species, have the anterior wings folded longitudinally, except 

 when they are used in flight; in the genus Sibyllina they are not folded. In the next 

 place, every true wasp has four submarginal cells, the fourth being very frequently 

 incomplete, but in some species of the genera Belonogaster, Polistes, and also of the 

 genus Vespa, among the social wasps, and in the solitary group, in the genera Zuthus, 

 llhynchium, Abispa and Synagris, the fourth cell is complete ; but I know no species 

 ol wasp that has not three complete submarginal cells ; the genus Sibyllina has only 

 two. Then, every true wasp has three discoidal cells in the anterior wings ; Sibyllina 

 has only one. The prothorax in all the Vespidae forms the upper anterior portion, and 

 is prolonged backwards to the tegulae of the wings ; the prolongations also forming 

 lateral portions of the upper surface: this is not the case in the genus Sibyllina. The 

 only character which Sibyllina possesses in common with the Vespidae is that of having 

 lunate, or notched, eyes : ibis I regard as only a subsidiary character, being common to 

 a vast number of Hymenopterous insects. We find the lunate eye in many species of 

 the genera Mutilla, Scolia, Sapyga, Pemphredon and Philanthus: then again, 

 among the Ichneumonidae, it is found in species belonging to the genera Pimpla, 

 Camploplex, Anomalon, Ophion and some others; this character therefore cannot be 

 regarded as any strong evidence in favour of Sibyllina being a genus of Vespidae. It 

 is a fundamental charactar, distinguishing the social wasps, that the claws of the tarsi 

 are all simple — in Sii)yllina the claws of the posterior tarsi are toothed ; — the solitary 

 wasps are distinguished by having the claws of the tarsi dentate. 



'* After a very careful examination of the insect, I have come to the conclusion 

 that Sibyllina belongs to the Ichneumonidas. 



"The first, and the strongest objection that can be urged against this opinion, will 

 doubtless be that the antennae are only twelve-jointed, and not, as in the generality of 

 tlie Ichneumonidae, niullianiculate : this is undoubtedly true, but there are genera of 

 Ichneumonidae hiiving only twelve- and thirteen-jointed antennas. Among the minute 

 Ichneumons the genus Trioxys is found to have thirteen-jointed antennae; and in 

 Ephidrus, belonging to the same group, they are only twelve-jointed. In the next place, 

 I believe every species of the larger group of Ichneumons, (I am not prepared to speak 



