280 Mr. J. W. Dunning on Acejitropiis. 



plant below the surface ; whilst the other females which 

 he bred were observed swimming both on and in the 

 water ; and lastly, that the female dives down to lay her 

 effffs under water on the Potamoaeton leaves, and that, 

 after laying them, she remains under water on the leaves. 

 In short, the female with rudimentary wings dwells prin- 

 cipally under water ; and though the male is not quite so 

 amphibious, he seems to have no objection to a dive {vide 

 Tr. Ent. Soc. 1872, p. 138). Reutti, as reported by 

 Heinemann, says that the female swims on her back 

 under the water ; and on this point there is a direct con- 

 flict between him and Ritsema, for the latter says that in 

 the evening the female comes to the top and swims about 

 on the surface, with her abdomen turned upwards. And 

 it seems more probable that she should thus attract the 

 males, which sit sluggishly by day on any object near the 

 water and fly briskly in the evening over the surface of 

 the water. But having thus attracted her mate, there is 

 nothing in Ritsema's observation to negative Reutti's 

 account of her drawing him down into the water with 

 her. The subject requires further investigation as regards 

 the wingless female ; whilst, as regards the winged form, 

 no one has yet been fortunate enough to detect her in 

 Jiagrante delicto. 



On the main point, the specific identity of the two 

 forms, I think no reasonable doubt remains ; but it is to 

 be hoped that Heer Ritsema will continue his observa- 

 tions, since there are many, and I am one, Avho will be 

 satisfied with nothing short of absolute demonstration, by 

 breeding; both forms of female from the same batch of 

 eggs, or, which would be equally conclusive, rearing lati- 

 yennis females from eggs laid by a niveus mother. 



