34 



Both these insects are also local, being restricted, like 

 athalia, and indeed all other species of the genus, to small 

 holdings hereand there throughout the area of their distribution. 



In the case which I exhibit this evening you will find 

 series of Melit&a athalia from Sussex, Essex, North Devon, 

 and Switzerland. In the last row but one is a specimen of 

 Melitcza dictynna from Switzerland, and below it one of the 

 North Devon examples of athalia, which is not altogether 

 unlike the Swiss insect. 



In the last row are three specimens of M. partheuie from 

 Switzerland. These are put in so that you may compare 

 them with the Swiss M. athalia. I think you will agree with 

 me that the Swiss athalia favours partheuie rather than the 

 British athalia, as regards colour and pattern of the upper 

 wing surfaces. As already adverted to, some of the North 

 Devon atlialia resemble partheuie on the under sides. 



Next to partheuie you will observe two examples of M. 

 aurelia (Swiss), and below them two North Devon athalia. 

 I think that you will admit that the foreigner and the Britisher 

 are exceedingly alike. 



When I first observed the resemblance of these specimens 

 to M. aurelia, I was inclined to send a note to our Entomo- 

 logical journals regarding the capture of this species in Britain. 

 Further comparison of British with Swiss M. atJialia, and 

 these again with Swiss M. aurelia and M. partheuie induced 

 me to suspect that these last-named insects might not be 

 distinct species, but only forms of M. athalia. 



However, I have at the present moment no strong 

 evidence to offer in support of my supposition. I must there- 

 fore let it remain in abeyance until I have collected more 

 facts and additional material, when I may be enabled to put 

 the whole matter before you in a more complete form." 



Mr. Step read a short paper on the Freshwater Mussels 

 (Auodonta cyguea and anatiua), which he illustrated by speci- 

 mens and diagrams. The species were said to be widely 

 distributed over the lakes and rivers of the country. Com- 

 mencing with a description of the shell, its hinge and the 

 muscles by which the valves arc held together, the reader 



