308 ENTOMOLOGICAL SOCIETY 



Vespidae and the Sapygidae and tends to confirm the correctness 

 of my views, in having removed the Vespidae from near the 

 Apidae, or bees, to a position among the fossorial wasps, be 

 tween the Pompilidae, Sapygidae, and Scoliidae. 



It is hardly necessary for me here to enter into a description of 

 the peculiarities of structure of this insect, since these may be as 

 certained from the excellent description and figures given by 

 Westwood in his Thesaurus and in the discussions recorded 

 above. 



In closing, however, I will give my reasons for believing this 

 insect to be neither a Braconid nor an Ichneumonid ; my rea 

 sons for considering it to be an Aculeate ; and why I consider it 

 entitled to family rank. 



My reasons for believing it to be neither a Braconid nor an 

 Ichneumonid are as follows : 



(i) Because the venter in the Ichneumonidae and the Bracon- 

 idae is soft and membranous ; in Rhopalosoma it is hard and 

 chitinous like all true Aculeates ; (2) because it has a true sting 

 which issues from the tip of the abdomen ; although the ovipositor 

 in a Terebrant may sometimes be capable of inflicting a sting, it 

 never issues from the tip of the abdomen ; (3) because the vena 

 tion is quite distinct from all Terebrants ; (4) because the tro- 

 chanters are i-jointed, while, as already pointed out by Westwood, 

 in the Ichneumonidse and Braconidae the trochanters are always 

 distinctly 2- jointed ; and (5) because the legs are strictly fossorial, 

 although entirely different from any known Hymenopter. 



I consider it to be an Aculeate Hymenopter : 



(i) Because the ovipositor is short, stout and sharp, issues 

 from the tip of the abdomen, and is in every sense "a sting; " 

 (2) because of its convex, hard chitinous venter; (3) because 

 the venation of the wings more nearly resembles that of the 

 Scoliidae, the curvature in the lower outer angle of the first dis- 

 coidal cell being a peculiarity of Scolia, while the venation of 

 the hind wings, except in some minute details, is exactly like that 

 of Dielis and totally dissimilar to any known Terebrant ; (4) 

 because the emarginated eyes appear to me to resemble more 

 closely those found in Sapyga, Eumenes, and My zinc, than 

 those found in certain Ichneumonids ; and (5) because the num 

 ber of joints in the antennae, 12 in 9 and 13 in J% is a feature 

 peculiar to the Aculeata and extremely rare with the Tere 

 brant ia. 



Rhopalosoma is believed to be entitled to family rank : (i) 

 because the venation of the front wings, although similar to 

 some Aculeates, is really quite distinct from all other known 

 forms; (2) because of the large prominent ocelli ; (3) because 

 of the structure of the antennae, the flagellar joints all being very 



