( xx ) 



thought at the same time that Mr. Poulton had rightly 

 attributed to them a sense of the force of gravity, as it would 

 be difficult to see what other sense could guide them to 

 whichever part happened to be uppermost of a closed box 

 kept in the pocket. With regard to the dark spots observed 

 by Mr. Poulton in the larvae of (i. HbatHx immediately before 

 pupation, he had seen a similar appearance in the case of a 

 large parasitic hymenopterous larva. 



Mr. Poulton, in reply to tbe first question, said that no 

 special receptacle existed in the flagellum, but that the blood 

 found its way in the lacunae between the structures in the 

 organ. In reply to the second, he said that observations on 

 the minute structure of the muscle would no doubt be very 

 interesting, but had not yet been made ; and that the very 

 same reasoning used by Dr. Dixey had occurred to him on 

 first observing the extraordinary contraction of the retractor 

 muscle. Mr. Poulton hoped to undertake the histological 

 investigation, which certainly promised good results if unusual 

 functional activity were attended by a correspondingly unusual 

 minute structure. 



He explained that the statement in the paper was that 

 Lord Walsingham had first called his attention to the pro- 

 thoracic glands of larvae. 



He wished to add to Dr. Dixey' s arguments in favour of 

 the appreciation of gravity by fallen larva? as a guide in 

 regaining their food-plant — the conclusion that larvae cannot 

 see in the true sense of the word. He thought that many 

 experiments and observations seemed to render it probable 

 that the ocelli are of no value as a guide to the movements of 

 larvae. He had covered the ocelli of numbers of larvae with 

 an opaque black varnish, which had been renewed at every 

 change of skin, but no difference could be observed between 

 the movements of these and the normal larvae. He therefore 

 argued that it was extremely improbable that the larvae could 

 regain the distant leaves of a tree from which they had fallen 

 by the guidance of the sense of sight ; and as a matter of fact 

 such larvae are often seen to ascend walls, palings, or other 

 objects, which do not lead to any food, as if acting under a 

 blind impulse to move upwards. Mr. Poulton argued that if 



