110 ZOOLOGY. 



found, not only on rape, but also on the different kinds 

 of cabbage, and on turnip plants. In the last case 

 they often occur in such numbers that the turnips do 

 not develop at all, and the overground parts also 

 remain small. There is a similar form {G. assimilis), 

 as large as the preceding species, but somewhat slimmer, 

 and, on account of greater hairiness, greyer. Appears 

 in spring onflowering rape and several kinds of cabbage, 

 as ■well as on similar cruciferous plants. It is harmful 

 because the beetles gnaw the buds and flowers, and 

 the larvae feed on the seeds within the pods. The 

 attacked pods ripen early, and open so that the larvae 

 fall to the ground, where they become pupae. Usually 

 only a single larva is found in each pod. The Rape 

 Gall Weevil (0. napi), somewhat larger than the two 

 preceding species, has a neck-shield which projects 

 strongly forward like a coUar, and is marked by a 

 median longitudinal furrow. It is covered with 

 yellowish-grey hairs. At the time when rape blooms 

 it appears upon the flowers. The female lays her 

 eggs singly in a hole previously bored in the stalk by 

 her proboscis ; during spring and early summer the 

 larva eats out the stem, which turns brown inside, 

 and becomes diseased or even dies. 



Family : Chrysomelidse (Leaf Beetles). 



Small, generally thick-set beetles, arched on the 

 upper side, with eleven-jointed antennae thickening 

 somewhat towards their tips, and four-jointed feet. 

 The first joints of the feet are covered with felt-like 

 hairs on their under sides (Fig. 81). The larvse have 

 three pairs of thoracic feet, and, in addition to this, 

 there are in most species a pair of caudal pro-legs. 

 Live in the inside parts of plants (stems, leaves), and 

 are_ usually elongated and yellowish white ; those 

 which live on the outside of plants are more convex, 

 shorter, and thicker, more or less hairy, often of a 



