OF WASHINGTON. 309 



long and slender and all armed above with a slender spine at 

 tip ; (4) because of the abnormally developed legs in the female, 

 the tarsal joints 2, 3, and 4 being dilated and deeply lobed at 

 apex, the incision being filled with a membrane, which evidently 

 materially aids the insect in making its burrows into light 

 sandy soil ; (5) because of the remarkable length of the tibial 

 spurs in both sexes, the inner being almost as long as the long 

 basal tarsal joint ; and (6) because of the peculiarities of the 

 spiny armature and the bifid claws. 



RHOPALOSOMA CRESSON. 



1865. Rhopalosoma Cr., Proc. Ent. Soc. Phil., vol. iv, p. 58. 

 1868. Sibyllina Westw., Trans. Ent. Soc. Lond., pt. iv (Dec.), p. 329. 

 (S. aenigmatica.) 



1868. Smith, 1. c. Proc., Nov. 16, p. xli. 



1869. 1. c. Proc., p. li. 



1874. Rhopalosoma Westw., Thes. Ent. Oxon., p. 130, pi. xxiv, f. 9. 

 1894. Dalla Torre, Cat. Hym. ix, p. 113. 



(Type R.poeyiCr.} 



The paper was discussed by Messrs. Marlatt, Schwarz, Gill, 

 and Uhler. Mr. Marlatt expressed his conviction as to the ac 

 curacy of Mr. Ashmead's conclusions, but took exception as to 

 Mr. Ashmead's general statement that the sting of the aculeate 

 Hymenoptera issues from the tip of the abdomen, whereas the 

 ovipositor of the terebrant Hymenoptera does not issue from the 

 tip. Mr. Marlatt said that while this distinction is apparent it 

 is not real. Homologically, the two organs are the same and 

 their point of issuing or attachment is also the same. In the 

 aculeate Hymenoptera, the ventral segments fold in such a way 

 as to obscure the point of origin of the sting. 



Mr. Ashmead in reply said that Mr. Marlatt was undoubtedly 

 correct and that the homology of the two organs has been 

 strengthened by the recent finding of a poison gland among cer 

 tain terebrant Hymenoptera. The character of which he had 

 made use, however, was equally valuable as a means of distin 

 guishing between the two groups. Mr. Marlatt had practically 

 criticised simply the form of words, and not the validity of the 

 character used. Mr. Schwarz said that, from the general ap 

 pearance of the insect exhibited by Mr. Ashmead, he would by 

 no means call it a fossorial species. The legs were not at all 



