226 PEESH-WATEB AQXTAEIA.. 



glass cut to fit, and stocked -with sucli aquatic plants as 

 protrude in their growth above the surface of the water, 

 choosing, if possible, those upon which the different species of 

 beetles are accustomed to feed — e.g., Water Plantain {Alisma 

 Plantago) for the Weevil, Hydronomus alismatis and the 

 Arrow-head {Sagittaria sagiUifolia) for the Galleruca 

 sagittaricB, &c. 



The Donaciadw are very beautiful beetles, and are divided 

 into the genera Donaeia and Hcemonia, the former containing 

 nineteen species and the latter two. All of them are her- 

 bivorous, gregarious, and of more or less lovely metallic 

 colours. They are nearly always found upon water-plants, 

 in the stems of which their larvse live, and at or near the 

 roots their pupae are inclosed in silk-like cocoons. The under- 

 part of these beetles is covered with downy hair, and then- 

 legs and tarsi are very strong. Their bodies are generally 

 elongated, their thoraces are narrow, and their elytra are 

 rather flat. As a rule, these beetles do not take to the water 

 unless it be to escape capture ; and their swimming under 



such circumstances is not 

 much more than a struggle 

 to regain the plant from 

 which they fell, or its neigh- 

 bour. 



Donaeia dentata (Fig. 

 143) is a species generally 



found upon floating leaves. 

 Fig, 143. DONACIA dentata. , ■:, i? ii ttt x 



such as those oi the W ater- 



Lily or Pond- Weed. Its 

 strong hind-legs are furnished with two teeth or spiues. 

 The elytra are of a brassy colour, and the legs are reddish. 

 There is a glossy pile beneath the body. 



The ChrysomelidcB, or Golden Apple Beetles, are as beauti- 

 fully coloured as the Donaciadce, but are of a different shape, 

 being very convex above and flat beneath. Their length 

 varies from about ^ia. to ^in. Their heads are not sunk in 

 the thoraces, and their antennae are rather short, gradually 

 thickening towards the tips. Chrysomela polUa is a common 



