( xxxii ) 



Mr. W. L. Distant communicated a paper entitled " Con- 

 tributions to a knowledge of the Homopterous family Ful- 

 goridfB," 



Mr. Oswald Latter read a paper, — which was illustrated 

 by the Society's new oxy-hydrogen lantern, — entitled " The 

 Secretion of Potassium-hydroxide by Dicranura viniila, and 

 the emergence of the imago from the cocoon." The author 

 stated that the imago produced, probably from the mouth, a 

 solution of caustic potash for the purpose of softening the 

 cocoon. The solution was obtained for analysis by causing 

 the moths to perforate artificial cocoons made of filter paper. 

 The imago emerges wearing over its head and eyes the 

 corresponding structures of the pupal stage : these serve as a 

 shield, and protect the underlying parts of the imago. The 

 shield is locked on to the head of the imago by hooks fitting 

 into sockets on the head. Prom beneath the shield project 

 a pair of sharp hard processes from the labrum of the imago. 

 These serve as instruments of attack upon the walls of the 

 cocoon, and tear away the portions successively moistened by 

 the alkaline secretion. 



Professor Meldola said that the larva of D. vinula secretes 

 strong formic acid, and Mr. Latter had now shown that the 

 imago secretes potassium-hydroxide, a strong alkali. He stated 

 that he had long been familiar with the fact that the secretion 

 from the imago of D. vinuJa was alkaline to test-paper, but 

 he had never investigated its composition ; and he also stated 

 that the fact that any animal secreted a strong caustic alkali 

 was a new one. 



Mr. Merrifield asked Mr. Latter if he had tried the converse 

 experiment, and proved that potassium-hydroxide would 

 soften the cocoon. Mr. Latter stated that he had done so. 



Mr. J. F. Hanbury asked if Mr. Latter could say where the 

 potassium was obtained by the larva. Mr. Latter said he 

 thought it was obtained from the leaves on which the larva fed. 



Mr. Gahan, Mr. Poulton, Mr. Merrifield, and Prof. Meldola 

 continued the discussion. 



Mr. H. J. Elwes and Mr. J. Edwards read a paper — also 

 illustrated by the oxy-hydrogen lantern — entitled " A revision 

 of the genus Ypthima, principally founded on the form of the 

 genitalia in the male sex." 



