192 Dr. T. A. Chapman on the Parasitism 



give an accurate sketch of the life-history of Bhi^^iphoruSj and 

 to be in harmony with all the facts yet recorded both of Rhi- 

 pipJiorus itself and of other parasites whose similar habits 

 render their history fairly available in explaining that oiRhi- 

 pijyhorus. The account there given is that RMpipliorxis " de- 

 posits its ^^g upon the grub of the wasp at the moment it 

 assumes the j)upa [i. e. spins or covers itself in the cell) ; as 

 soon as the egg is hatched, it devours the grub of the wasp 

 entirely, and itself assumes the pupa- and imago-form in the 

 cell of the wasp." 



The mode of oviposition here noted of RMpipihorus is, I 

 believe, that followed by it, although it will be seen tliat I am 

 here at issue not only with Mr. Murray, but also with Mr. 

 Smith, with whom on all other points I agree. If Mr. Deni- 

 son's view (but for the slight disagreement noted, I should 

 here, as I shall in the rest of these remarks, have said Mr. 

 Smith's view) of the hi^iox j ,oi RhipipJwrus is correct, the 

 relation of RJdp)iphorus to the wasp is, mutatis mutandis^ pre- 

 cisely the same as that of Chrysis bidentata to Odynerns spi-^ 

 nipes. The larva of Chrysis hidentata feeds on that of the 

 solitary wasp, from whose cocoon emerges, not the was}), but 

 the Chrysis. Now in this instance the egg of the parasite is 

 not laid until after the larva of the wasp has done feeding, 

 and is spinning its cocoon. Before I ascertained this fact, I 

 had formed the same theory as to the period of oviposition as 

 Mr. Smith has done in the case of the RhipiphoriiSj and made 

 in consequence many a vain search for the egg of Chrysis hi- 

 dentata beside the feeding larva of the Odynerus. The parent 

 Chrysis has many more difficulties to overcome (what these 

 are is not material to the present subject) in depositing her 

 eggs than the Rhipiphorxis^ to whom it must be as easy to 

 deposit an egg beside a full-fed larva, during or just before 

 spinning, as in an empty cell. There are other instances re- 

 corded of parasites similarly depositing their eggs beside full- 

 fed larva?, none, that I know of, of an egg remaining dormant 

 beside a feeding larva. Mr. Murray appears to interpret Mr. 

 Smith's view to be that the larva of Wiipiphorus hatches at 

 the same time as that of the wasp, and then walks off to find 

 a full-fed larva to eat. I quite agree with Mr. Murray's com- 

 ments on such a theory, but feel satisfied that Mr. Smith 

 really meant that the egg lay dormant until its companion, 

 the egg of the wasp, was a full-fed larva. 



The two eggs found by Mr. Murray in some cells of the 

 wasp both appear to me to be undoubtedly eggs of the wasp. 

 I think it extremely improbable that the egg of Rhipipyhorus 

 should be precisely the same as, however similar it may be to, 



