Two new Strepsipterous Insects. 55 



saccharine essences, possibly in a less condensed form ? At all 

 events I feel assured, from the circumstances under which I have 

 usually found them, as already narrated, that their alleged parasi- 

 tical habits will ere long be disproved, as in the case of Ceraiina. 



It should also be remarked, that it is not an uncommon occur- 

 rence for briars previously occupied by the progeny of one insect, 

 to be again made available by a different insect after the original 

 tenants have quitted their abode ; and that on one occasion I found 

 some pupae of Hylceus ensconced in a mud-cased briar containing 

 the deserted cells of an Odynerus ; the Hylcei in this instance 

 being arranged obliquely, on account of the large diameter of the 

 excavated channel (as in the briar marked C, to which is ap- 

 pended a specimen of the Hylceus reared therefrom, and some of 

 the pupae in spirits). It will however scarcely be contended that 

 the Hylcei in this instance were parasitical feeders upon the store 

 laid up for the Zoophagous Odynerus larvae, nor is there any trace 

 of subsequent occupation by an Osmia. 



The same remarks equally apply to another briar (now exhibited 

 and marked _D), the lower end of which I found to be tenanted 

 by three larvae of Cemonus, with several others of Hylceus above, 

 the tapestry of the latter serving to determine the limits of each : 

 but, having carefully reunited the split portions of the briar for 

 the purpose of ascertaining the result of this joint occupancy, the 

 time for the appearance of the perfect Cemoni being prior to that 

 of the Hylcei, the former alone were produced, having annihilated 

 the latter while effecting their exit towards the middle of May ; 

 and it would seem not improbable that a similar result should 

 ensue in the briars occupied by Osmia and Hylceus as aforesaid, 

 unless the progeny of the original constructor be altogether pre- 

 cluded from issuing, there being no other opening for the purpose, 

 nor do the Osmice ever perforate the side of the briar ; and the 

 lodgment of the Hylceus being subsequently effected, the former 

 must have belonged to a species which attains maturity before the 

 latter, — like the Osmia ruborum of the French writers already re- 

 ferred to, produced early in May. 



The Trypoxylon also is not averse to profit by such opportu- 

 nities of economizing labour; which the same writers characterize 

 as " une sorte d'intelligence industrielle," surpassing the ordinary 

 inspirations of instinct, although not unattended with risk. This 

 insect however usually prepares for its larvae a gallery, with cells 

 proportioned to their size, excavated amid the main body of pith. 

 The distinction which the same writers have pointed out, between 

 such casual appropriations of a deserted tenement, from which the 



