306 ENTOMOLOGICAL SOCIETY 



IchneumonidaB. " yth, Because, amongst the minute (Adscitous) 

 groups, species exist having only i2-jointed antennae (Ephedrus) 

 and others having i3-jointed antennae (Trioxys)." 8th, Mr. 

 Smith states " that in Rhopalosoma a distinct second joint in the 

 trochanters is quite as visible as in the Ichneumonideous genus 

 Metopius. 9th, The antennae of every known species of wasp 

 are geniculate, which is not .the case in Rhopalosoma. loth, 

 The prothorax of Rhopalosoma is of the same structure as Ophion 

 and Anomalon. nth, The ocelli are large and prominent in 

 Rhopalosoma. as in the two last-named genera ; in the Vespidae 

 they are much smaller and usually more sunken than prominent. 

 1 2th, The broadly dilated tarsi in Rhopalosoma do not occur in 

 Vespidae, but are peculiarly characteristic of Anomalon. i3th, 

 The basal segment of the abdomen of Rhopalosoma agrees with 

 that of Ophion and Anomalon, as well as Belonogaster and 

 Vespa." 



Although thus pointing out the relationship of the genus with 

 Ophion and Anomalon, Mr. Smith admitted its want of strong 

 affinity with any other known insect. 



Prof. Westwood, to these objections, replied as follows : 



1 . Some of the most aberrant wasp genera, and the remainder 

 of the Aculeata, have flat wings. 



2. Rhopalosoma has three submarginal cells. In all the gen 

 uine Ichneumons, the first submarginal and the anterior cliscoidal 

 cells are thrown together. Even in those Adsciti which have 

 three distinct submarginal cells, the first (and only) recurrent 

 vein enters the first submarginal cell, and not the second, as in 

 Rhopalsoma. 



3. Rhopalosoma has three discoidal cells, the lower outer one 

 having its extremity partially closed by a transverse, nearly ob 

 solete vein. 



4. The collar of Rhopalosoma extends back laterally to the 

 tegulas, although not seen dorsally at the sides of the thorax. 



5. The eyes of Rhopalosoma are not lunate but oval, with a 

 small emargination in the middle of the inner margin. 



6. The ungues in Rhopalosoma are furnished beneath with two 

 obtuse spines. 



7. No species of Adscitous Ichneumon, nor indeed any other 

 terebrant Hymenopterous insect, is known possessing i3-jointed 

 antennae in the males and 12 in the females. This is one of the 

 leading characters of Aculeata. 



8. I cannot discover a second joint in the trochanters of Rho 

 palosoma. Its existence is one of the leading characters of the 

 terebrant Hymenoptera. In certain positions, a faint appearance 

 of an articulation near the base of the femora may be observed. 



