GALLS CAUSED BY BEETLES 49 



south of England. Similar galls are caused on this plant 

 by M. Unariae. 



The swollen ovaries of the Figwort, Marsh Speedwell, 

 and Brooklime, result from the presence of the larvae of 

 M. beccabungae. Members of the allied family, Plantaginaceae, 

 are also attacked by species of Mecinus. The larva of 

 M. collaris causes an elongated swelling on the floral axis of 

 the Seaside Plantain. The flower head of the Hoary 

 Plantain is sometimes galled by Mecinus pyraster (see 

 Plate VI., where Fig. i shows a normal flower spike con- 

 trasted with an afflicted one. Fig. 2, containing the larva). 

 The beetle (magnified; it is only 4 mm. long) is shown 

 in Fig. 3. It is widely distributed. It also galls the floral 

 axis of the Ribwort Plantain. 



Many cruciferous plants are attacked by beetles of the 

 genus Ceuihorrhynchus. The galls, for the most psBrt, are 

 rounded or fusiform swellings at the base of the stem and 

 on the roots. The most familiar of all coleopterous galls 

 are those caused by the presence of the larvae of Ceuihor- 

 rhynchus sulcicolUs Gyllenhal (pleurostigma Marsh) on the roots 

 of Turnips, Swedes, and various kinds of Cabbage. They 

 are often coalescent ; a single gall is a smooth rounded 

 protuberance, usually about the size of a large pea, situated 

 on the upper part of the root, just below the surface of the 

 ground. The beetle is minute, about 3 mm. long. The 

 elbowed antennae are situated on the long, stout proboscis, 

 a characteristic of the weevil family (Curculionidae) to 

 which these beetles belong. The eggs are generally de- 

 posited in holes made by the proboscis, usually one in each 

 hole. The larvae are yellowish-white, thick, legless, and 

 armed with dark brown jaws. They are at first difficult to 

 observe within the gall, but later they hollow out its centre 

 and are easily found. When full fed, the larva leaves the 

 gall, and makes a hard case of earth, etc., in which it 

 pupates. The imago emerges about six weeks or two 

 months later. This gall may be found throughout the 

 year, sometimes with living tenants even in severe weather. 

 4 



