^ Ivi ) 



The parasites and hyperparasites emerged from the swollen 

 body of both species of Macrosiphum, whereas in Drepano- 

 siphum the Braconid larva emerged and constructed beneath 

 its host a beautiful disc- or button-shaped cocoon from which 

 also the hyperparasites, when present, emerged. Into the 

 roof of this cocoon the ventral surface of the host was woven. 



The Chalcid parasite of Vanessa urticae, L., waiting 

 beside the larva preparing for pupation. golden pupae 

 NOT CAUSED BY PARASITISM. — Prof. PouLTON exhibited 22 

 males and 11 female Pteromalus, sp., together with the Vanessid 

 pupal shell from which they had emerged. The female parent 

 had been seen, on Aug. 17 last, at St. Helens, Isle of Wight, 

 patiently waiting beside the butterfly larva, which was rest- 

 ing motionless on a grey stone wall before it had suspended 

 itself, and therefore many hours before pupation. On Aug. 20 

 the pupa was removed, and on Sept. 22 all the exhibited 

 specimens of Pteromalus had emerged and were found alive 

 and active. The life-cycle thus contrasted sharply with 

 examples (6 males, 48 females) of Pteromalus puparum, L., 

 much larger in average size, bred from Pyrameis atalanta, L., 

 in 1900-01. In this case the female Chalcid had been found 

 seated on the fresh moist pupa, Sept. 7, 1900, at Calverley 

 station, near Bradford, Yorkshire. Ova were laid on this or 

 the following day, and the offspring emerged at Oxford on 

 May 22, 1901. 



The pupal shell of the F. urticae was grey, as could still 

 be seen, and harmonized well with the stone wall, showing 

 that the power of colour adjustment was not removed, as 

 some have supposed, by the presence of parasites. The 

 normal effect of the green leaves of the nettle was to produce 

 golden pupae — the nearest approach to green of which this 

 species was capable. Such golden pupae were sometimes 

 parasitised, but so were the dark pupae, as exemplified by 

 the exhibited specimen. In former years Prof. Poulton had, 

 by the use of the appropriate backgrounds, bred hundreds of 

 healthy golden pupae which produced normal butterflies. 

 The opaque cuticle of a parasitised dark pupa showed no 

 change, but the transparent cuticle of a parasitised golden 

 one took on a peculiar brassy appearance, probably due to 



