103 



Mr. Hardy said that he had given the subject some attention, and made 

 some observations upon the air-sacs, with regard to their ultimate use. Two 

 very thin and transparent bodies were attached to the air-sacs (reniform 

 bodies) of the thorax ; these bodies, as the air-sacs gradually extended to- 

 wards the head, were developed into long ear-shaped sacs while inside the 

 body of the larva. When these were perfected, they quickly made their 

 way out of the thorax behind the head, and appeared as two lobes having 

 a peculiar ear-like appearance. They evidently acted as buoys to the now 

 developed pupa, and seemed to have deprived the original air-sacs of their 

 contents, for the latter broke up and dispersed after the extension of the 

 ear-like lobes. While this was going on at the head, the air-sacs of the tail 

 were also tending outward, and at about the same time as the lobes appeared 

 at the head, the sacs of the tail were developed externally into two large 

 flat branchial lobes, having little floating power, so that the pupa swam 

 perpendicularly head upwards. He had also reason to believe that similar 

 larvae underwent another transformation, and appeared as pupae swimming 

 head downwards. These latter developed into the gnat (Culex), while the 

 former pupae developed into Corethra plumicornis. 



The President said that it would be interesting to get the eggs, and ascer- 

 tain when the air-sacs were first formed. 



Mr. Hardy considered that there was a second pupal condition to prepare 

 the insect for its aerial existence, 



Mr. Freeman doubted the transformation of the Corethra larva into the 

 perfect form of a Culex. 



The President described the contractile effect produced upon the muscles 

 by treatment with acetic acid. 



A vote of thanks to the President for his paper was proposed by Dr. 

 Matthews, and carried unanimously. 



Mr. Gilburt described the process of development and liberation of the 

 zoospores of Vaucharia, which was at that time abundant at the water- 

 works of the East London Water Company at Hackney Marshes, the plant 

 being in the most favourable condition for the examination of this interest- 

 ing portion of its life history. 



The President announced the engagements for the ensuing month, and 

 the proceedings concluded with the usual Conversazione, at which the fol- 

 lowing objects were exhibited : — 



Larva of Corethra plumicornis ... ... The President. 



Section of stem of Mistletoe, stained ... Mr. F. W. Andrew. 



Ship's Barnacles ... ... ... ... Mr. H. Epps. 



Head and leg of Crab ro cibarius ... ... Mr. H. E. Freeman. 



Fang and poison-bag of American Centipede... Mr. H. R.Gregory. 



Vblvox globator, mounted in a solution of) ., T „ T 

 . . y ' £ Mr. J. E. Iugpen. 



iodine and potash ... ... ) 



Nest Qf a trap-door Spider from South ) r> • M Hh 

 America ... ... ... > 



Attendance — Members, 56 ; Visitors, 5. 



