540 PHYSIOLOGY. 







which all the fields of a farmer were entirely destroyed, and hu and 

 his labourers collected eighty bushels of them. The larvae of Hoplia 

 pulverulenta, H. graminicola, and H. argentea, dwell in humid mea- 

 dows, where they destroy the roots of the different grasses. Some few 

 years ago I myself discovered all the blades of high grass of this descrip- 

 tion completely covered with the perfect H. argentea. 



It is especially among the Curculips that we find larvae which are 

 destructive to roots; but less so among the other families, yet the larva 

 of Lathridius porcaius, according to Kyber *, feeds at the roots of 

 Rhapkanus saiivus, and especially 'in that of the variety known by 

 the name of the radish. Kirby and Spence reared from a small larva 

 that was found in the root of Sinapis arvensis the Gurculio contractus, 

 Msh., and the Rh. assimilis, Fab., two species of insects belonging to 

 the genus Ceutorhynchus, which, even as perfect insects, like all their 

 congeners, attack the young shoots of plants. 



Besides the above larvae of the beetles, many of the maggots of the 

 Diptera are fond of the roots of plants. Thus the maggot of a fly has 

 been found in a carrot (the root of Daucus carola), but it was not 

 reared ; in the radish (the root of Rhaphanus salivas) the maggot of 

 Anihomya radicum, Meig. ; and in onions a similar maggot, which pro- 

 duced a fly that Kirby and Spence call Scatophaga ceparum. Other 

 dipterous larvae Reaumur t found in the bulbs of the narcissus, and 

 reared from them a fly belonging to the family of the Syrphodea, which 

 Meigen calls Merodon equesiris. The root also of the cauliflower feeds 

 the maggots of flies ; in that, as well as in the other varieties of the 

 cabbage, is found the maggot of the Tipula oleracea, Lin. 



Although the majority of the caterpillars of the Lepidoplera feed 

 upon the leaves of plants, yet there are some which prefer their young 

 roots; thus the caterpillar of Noctua (Episema, Tr.) graminis, Fab., 

 which consumes the tender roots of the softer grasses, and spares the 

 elder harder ones, for instance, those of Alopecurus pratensis, Lin., as 

 well as those of corn and of the Trifolium pratense, Lin. J 



303. 



Those insects, however, are more numerous which either bore into 

 the stems of plants or into the woody trunks of trees ; but their pre- 



* Germar's Mag. vol. ii. p. 1, &c. -f- Memoires, vol. iv. part xxxiv. 



^ Ochsenheimer Schmetterlinge von Europa fortges. von Treitschke, 5 t. part i. p. 1 'I'l. 



