PARASITIC HYMENOPTERA. 343 



cities y to which I have been determined principally by an 

 examination of the parts of the thorax,k and the position of the 

 petiole, which however presents a marked peculiarity.' 



Gen. I. — OocTONUS. Haliday. 



AntenncB maris XS-articidatce, femincE W-articulatcc capitulo 

 exannulato. Tarsi jientameri. 



A. Abdomine petiolato. 



His statura Polynemce fere, sed brevior abdomine magis rotundato, 

 pedibus brevioribus, alis breviter ciliatis, ulna brevi lineari : quoad 

 reliqua, caput thorax abdomen alseque satis conveniunt : antennas 

 femince scapo elongato utrinque attenuato, pedicello lato com- 

 presso, articulis flagelli longitudine subaequalibus aut intermediis 

 longioribus, exterioribus sensim incrassatis ; undecimus major 

 ovatus s. oblongus ; — maris articulis flagelli linearibus subequa- 

 libus. 



' I do not mean to venture an opinion, that the aggregate group is co-ordinate 

 with those which rank as families in the rest of this order. Till the contents of 

 the Pupivora are more fully investigated, the value of its sections must remain 

 exposed to doubt. When the natural groups shall have been recognized and 

 examined in detail, we may hope that some systematist of comprehensive mind 

 and adequate knowledge will assign them respectively to their proper grade, 

 perhaps a higher than is yet conceded to them. The Chalcides and Oxyuri 

 seem each to embrace more than one equivalent to such families as the 

 Ichneumones, Chry sides, and Gallicola. As to the Fcen'ideB, the chain is so inter- 

 rupted from the small number of genera, that it might be rash to divide it. The 

 family besides is, in its present form, far too convenient a receptacle for all stray 

 articles to be lightly resigned. I am obliged to enrich it further at the expense 

 of the Ichneumones with two genera — Stephanus and Plancus — which Pelecintts and 

 Fanus seem respectively to reclaim ; of the latter I am more doubtful ; for the 

 other I have the authority of Jurine and Spinola. 



^ Important as the structure of the aculeus is to the functions of these Hymen- 

 optera, its variations are to be admitted with great caution into the characters of 

 the higher groups, the more obvious differences often depending less on the 

 typical composition than on its greater or less development in length. Parallel 

 variations seem to be often reproduced in distinct families. Perhaps there is 

 no one character which has been more generally fixed on to distinguish the 

 GallicoliB than the spiral aculeus, but in Anacharis 7iitidula, Balm, there is nothing 

 to claim such an epithet Ka-r e^oxw ; the aculeus is simply subulate, shorter than 

 the last ventral segment in which it is contained, and it would demand a sharp 

 sight to single out any palpable difference in its form from the same organ of 

 Cinetus gracilis. 



' It may be added, that there are certain resemblances between species of this 

 tribe and the genus Evania, but so partial that I have not ventured to entertain 

 any conjecture as to their significance or tendency. 



