OF WASHINGTON, VOLUME XV, 1913 147 



externally. Each larval skin shows about ten spiracular open- 

 ings, and above the posterior six or seven are nearly circular mem- 

 branous areas. Anteriorly the exuviae are thickened, darker in 

 color and more shining, as indicated by the stippled areas in the 

 figure. 



-Air. Rohwer commented on Mr. Hood's paper as follows: 

 Air. Hood is to be congratulated for bringing before science these 

 interesting notes on one of the most remarkable Hymenopterous 

 insects known. Rhopalosoma Cresson is a genus which is very 

 difficult to place and many of the most able Hymenopterists have 

 expressed their views as to its systematic position. To give some 

 idea of the difficult}' in placing this genus the following summary of 

 locations it has occupied is given : Cresson described it as an anom- 

 alous Braconid; Haliday considered it as a Sphecid related in 

 some extent to Sceliphron; Westwood originally considered it re- 

 lated to the Vespidae, but later considered it as a fossorial Hymen- 

 opt eron; Smith at first placed it among the ants, but on closer 

 examination placed it in the parasitic Hymenoptera; Ashmead, 

 before this Society, in 1896, summed up the characters of this re- 

 markable genus and ended by making a new family for it, which he 

 placed in his heterogeneous superfamily Vespoidea; Alorley 1910, 

 states that it can be "placed nowhere among the Parasitica or 

 Terebrant Hymenoptera," and adds that no matter where it is 

 placed it will form an aberrant group. The author of these re- 

 marks believes that Ashmead was more nearly correct than any 

 of the other authors, but is of the opinion that the Ashmedian 

 superfamily Vespoidea could be well divided into a number of 

 smaller and more natural superfamilies (and such has already been 

 suggested by Air. Banks when he proposed the superfamily Scoli- 

 <>i<lea) and that Rhopalosoma and the allied genus Paniscominni 

 should form one of these superfamilies. 



Heretofore the habits of the immature stages of this curious 

 genus have remained unknown, and now that they have been out- 

 lined it is hoped that more study will be made of them, as it is very 

 likely that they will throw some light on the systematic position 

 of this interesting group. Even now one is confronted with the 

 remarkable resemblance between the larva of Rhopalosoma and 

 .-nine of the Dryinids (for habits of the Dryinida? see R. C. L. 



