WITH DESCRIPTIONS OF NEW SPECIES, &C. 23 



taken, and this renders the business extremely awkward. 

 In the ^^ Intelligencer," vol. 10, p. 149, Dr. Hagen in part 

 details a plan pursued in Germany by Professor von Siebold, 

 viz. to inclose the larvae or pupse in a bag, which is to be 

 half sunk in some shallow stream, and suspended at the top 

 to an overhanging branch ; but though this plan may be 

 easily pursued in private grounds, it is difficult to imagine 

 how long the bag would remain in position were it placed m 

 the open country, save in very secluded spots, of which there 

 are few sufficiently so, in this thickly populated country ; 

 nevertheless the plan is worth experin^enting upon by those 

 Entomologists who may reside in suitable localities. 



A very interesting account is given by Professor von 

 Siebold in the " Stettiner Entomologische Zeitung " for 1861, 

 p. 59, and by Dr. Hagen in the '' Intelligencer," vol. 10, 

 p. 148, of the habits of a species of Ichneumon {Agriotypus 

 armatus)^ which is parasitic upon the larvae of Silo pallipes. 

 It appears that when a larva is infested by the larva of this 

 Hynienopteron, it is not contented with the limited sphere of 

 observation to be found at the bottom of the stream, but 

 seeks to extends its knowledge of the surrounding waters, 

 and spins a long footstalk by which the case is elevated. 

 Dr. Hagen seems to be of opinion that this is caused by a 

 morbid craving of the affected larva. That gentleman, when 

 in London, showed me some cases so furnished, and it struck 

 me that it might be possible to account for it in another way. 

 [t is well known that the pupa of a Phryganideous insect, 

 when about to assume the perfect state, leaves the case and 

 swims to the surface, where it seeks a suitable position for 

 its final change, and it seems to be within the bounds of pos- 

 sibility that the pupa of the ichneumon, not possessing the 

 same natatory powers, may need this long peduncle to raise 

 the case to the surface, and so enable the imago to escape 



