I AQUATIC BEETLES 93 



By the end of June the larvae begin to pupate, and 

 during July the pupae may be found in great abund- 

 ance. The full-fed larva quits the water, and makes 

 a globular hole about half an inch deep in the mud or 

 clay of the bank, six inches or so above the water- 

 level. In this hole the pupa lies upon its back, kept 

 from contact with the moist earth by the long stiff 

 spines which stand out from its body. The abdomen 

 is flexible, and can be moved rapidly about when 

 the Insect is disturbed. Some larvae were found still 

 unchanged six days after leaving the water. Early 

 in August the fully developed Beetle begins to 

 show itself in numbers. At first whitish, its colour 

 darkens on exposure to light and air. It throngs the 

 shallow waters until cold weather drives it into the 

 mud, where it hibernates till spring. 



Very soon after the emergence of the Beetle the 

 cocoon is formed and the eggs are laid. Hence all 

 the stages may be found together about the end of 

 August — eggs, young larvae, pupae, and adult Beetles. 



DONACIA. 



The " leaf-eating Beetles " (Chrysomelidae) include 

 a number of species which pass their early stages 

 upon submerged plants, and feed upon the roots. 

 The white water-lily (Nymphaea), Potamogeton, the 

 Arrowhead, the Sedges, the Marsh Marigold, the Bul- 

 rush, the Horse-tail, and other moisture-loving plants 

 yield shelter to the various species of Donacia and its 

 close ally Haemonia. D. crassipes is often found 

 abundantly upon Nymphaea or Sparganium. The 



