480 



Art. LIX. — Essay on the Classification of Parasitic 

 Hymenoj)tera, %c. By A. H. Haliday, Esq. M.A. 



{Continued from page 350.) 



Of the Ichneiimones of the Second Line, (Ichneumones adsciti, 

 Essenbeck.) 



The authors who have treated of the family at large are 

 enumerated and noticed in detail by Professor Gravenhorst, 

 in the Prolegomena to his Histoi-y of European Ichneumones. 

 It was not till the year 1811 that this supplemental branch 

 was distinguished from the proper Ichneumones, by Doctor 

 Nees Von Essenbeck, whose system is more fully unfolded in 

 the ninth volume of the New Series of Transactions, published 

 by the Imperial Academy of the Physical Sciences,'' and has 

 been followed by modern entomologists with few exceptions. 

 That of Spinola, which Latreille adopted, and has adhered to 

 in his latest works, differs in result (as detailed by them) from 

 that first mentioned, only as respects the position of the 

 genus Agathis, whose affinity to the Bracones is admitted by 

 Latreille himself.^ But, accurately examined, this method 

 will be found to fail, as the variations of the palpi (on which 

 it is founded) are much more extensive than those it compre- 

 hends. That of Von Essenbeck is therefore as superior in 

 certainty as it is in facility of application; while the few 

 Apterous species'^ are, by their habit, easily assigned to their 

 proper station in the family. He has, however, employed the 

 principle of Spinola for the distinctive characters of his second- 

 ary groups, the Bracones and Bassi, a division which is 

 accordingly defective in a similar degree. The difficulty of 

 applying such a test appears from the fact that this most 

 accurate observer has made glaring transpositions,*^ even 

 among the genera strictly reducible to the lines of his own 

 method. Professor Fallen, in a recent Essay, while he adopts 

 the primary division of Von Essenbeck, has rejected these 

 minor groups ; but, in reducing the number and extending the 



* Nova Acta Phys.-Med. Acad. Csesar. Leop. Carol. Nat. Curios. 

 " R^gne Animal, N. E. Tom. V. p. 288. 



" I am acquainted with but two, Aphidius Ephippinm and Ahjsia aptera. 

 '^ Ctrlinius, Spatldus, Hormius, Blacus, Perilitus. 



