LEAF-EATING BEETLES. 



of the species he may find, as was done with the Ceramby- 

 cidas. This is partly because of technical difficulties, 

 including the large number of species, and partly because 

 many of the species are small and not usually noticed. 

 All of them are diurnal. 



The following hints may be useful. If the head is 

 constricted or neck-like behind the eyes, and the prothorax 

 is narrower than the combined elytra, the specimen belongs 

 to one of the following tribes: Donaciini, Sagrini, or 

 Criocerini. If the pronotum and elytra have broad, 

 expanded margins, the head concealed from above, and 

 the outline of the body ellipitical or nearly circular, see 

 Cassidini (p. 376). If the beetle is wedge-shaped, broad, 

 and square-cut behind, especially if the elytra are pitted 

 or have a net-work surface, see Hispini (p. 375). If the 

 hind femora are thickened, fitting the beetle for jumping, 

 and the antennas are rather close together at the base, see 

 Halticini (p. 372). As for the rest, the majority of those 

 usually noticed are either ChrysomeKni (antennae usually 

 further separated at the bases than the length of the first 

 joint; front coxae transverse and widely separated; third 

 tarsal joint rarely indented; see p. 368) or Galerucini 

 (antennas rather close together at base, inserted on the 

 front; front coxae conical and prominent; see p. 370). 



Donaciini 



In addition to the characters given above, this tribe may 

 be recognized by the fact that the first ventral, abdomi- 

 nal segment is about as long as all the others combined. 

 They look very much like certain Cerambycidas. Their 

 larvae live on the outside of the submerged roots of water- 

 lilies, skunk-cabbage, pickerel-weed, sedges, and other 

 aquatic or semi-aquatic plants. They pupate in cocoons, a 

 number of which are often fastened in a row to the stems 

 or roots of their food plants. The adults of Donacia are 

 commonly seen on the leaves of water lilies and other 

 aquatic plants in early summer, and fly from leaf to leaf 

 when disturbed. The color is usually more or less metallic 

 greenish, bronze, or purple; they are coated beneath with 

 a satiny pile of fine hair. Donacia has numerous species 



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