The Zoologist— February, 1869. 1567 



has only one. The pruthorax in all the Vespidte forms the ui)per anterior portion, and 

 is prolonged backwards to the teoulse of the wiiifjs ; 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 Vespidje is that of having^ 

 lunate, or notched, eyes : this 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, Ophiou and some others; this character therefore cannot be 

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

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

 are all simple — in Sibyllina 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 Ichneumonidae. 



"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 

 the Ichneumonidae, raultiarliculate : this is undoubtedly true, but there are genera of 

 Ichneumonidae having only twelve- and thirteen-jointed antenna;. Among the minute 

 Ichneumons the genus Trioxys is found to have ihirieen-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 

 of the minute ones in that particular) has double-jointed trochanters : these joints in 

 most of the genera and species are distinctly visible, but not universally so in the 

 group; in some species belonging to the genus Exetastes,the second joint is retracted 

 within the first, and is only partly visible ; the same is the case in the genus Anomalon. 

 I have carefully examined the structure of the legs of Sibyllina, and I find a second 

 joint distinctly visible, quite as much so as in the Ichneumonideous genus Metopius. 

 The antenna of every wasp that I have seen are geniculate, in Sibyllina they are not. 

 In addition to this, the prothorax is of the same structure as in Opliion and Anomalon ; 

 its ocelli are large and prominent, as in those genera, whilst in the Vespidae they are 

 much smaller, and usually more sunken than prominent. Another most remarkable 

 peculiarity in the structure of Sibyllina, is the broadly-dilated tarsal joints, a character 

 I believe nowhere to be found in the Vespida;, hut peculiarly characteristic of the 

 species of the genus Anomalon. The abdomen of Sibyllina has the basal segment 

 narrowed into a slender petiole; this is also characteristic of the genus Ophion and 

 Anomalon. Then again, Sibyllina is furnished with a sting, nr ovipositor; its structure 

 is precisely the same as the sting or ovipositor of Ophion and Anomalon : in fact I can 

 discover no external difference between the stings of Belonogaster, Vespa, Ophion and 

 Anomalon ; in each the sting tapers to a sharp point, and is simply a hollow tube, 

 having a groove beneath, that in the wasp being, I presume, for the purpose of convey- 

 ing poison into the wound made by piercing, and in the case of the Ichneumons for 

 conveying the egg into the victim attacked. 



" Place Sibyllina in any group of the Hymenoptera, and it will, as it were, stand 

 alone; it has little affinity that I can discover, certainly it has no strong aflBnity, with 

 any other known insect. But having pointed out those parts of its structure that agree 

 with the same parts in the genera Ophion and Anomalon, I shall conclude by 



