t 9 o 



[Proc. B.N.F.C. 



and Mr. Balfour-Browne mentioned that he had obtained eggs in 

 October, although the egg-laying period is usually given as being 

 March and April. He described the voracity of the Dytiscus larva, 

 which killed even newts and small fish, and gave in detail the 

 method by which these larvse sucked their food through a fine 

 tube which ran the length of each of the jaws, so that, although 

 possibly some solid food was taken by the mouth, most of the 

 nourishment was obtained as liquid, the larva actually injecting a 

 dissolving fluid into the prey to enable it to obtain more. The 

 larvae had been described as casting their skins at more or less 

 regular intervals of about ten days five or six times during their 

 life, but he found that the last stage of the larva ran from six to 

 eight weeks, while earlier stages occupied three weeks or less, and 

 from his experience with other aquatic larvse he believed that the 

 last larval stage was always longer than the previous ones. 

 Having referred to the terrestrial pupa of Dytiscus, Mr. Balfour- 

 Browne went on to describe the known facts with regard to 

 Hydrophilus, and he pointed out the great differences between it as 

 a representative of the Hydrophilidce and Dytiscus as an example 

 of the Dytiscidce. Whereas Dytiscus was specially adapted for 

 swimming Hydrophilus was a poor swimmer, its legs and general 

 form being specially adapted for crawling on the water-plants. 

 He further explained the entirely different method of breathing in 

 these two groups of beetles. Although Hydrophilus was only 

 found native in the South-East of England, he had kept the 

 species, obtained eggs, and reared the larvae to full size at 

 Holywood, although he had not yet got them to pupate. The 

 larval Hydrophilus fed on freshwater snails, and its manner of 

 feeding was most extraordinary. It seized the snail in its jaws, 

 bent its head back until the snail rested on the larva's back, and 

 then while the left jaw held the shell the right cut it through. 

 Having compared Dytiscus and Hydrophilus, Mr. Balfour-Browne 

 proceeded to describe Hydrobius, and showed that, although a 

 close relation of Hydrophilus, it differed in many points from it. 





