382 MODERN CLASSIFICATION OF INSECTS. 



species are ornamented with brilliant metallic tints. They are en- 

 tirely herbivorous, feeding, in the larva state, either upon or within 

 the leaves of various plants. 



De Geer has observed the transformations of two of the species of 

 the typical genus Galeruca, namely G. tanaceti Linn. {fig. tG. 16 — 

 21.) and G. nymphaeas Linn. {fig. ^Q. 14, 15.). The former is found 

 upon the vvild tansy, and the latter upon the leaves of the water-lily 

 and other aquatic plants. The larva {fig. 46. 21.) of the former 

 is a black fleshy grub, cylindric, but attenuated at each end, each 

 segment of the body being furnished with several elevated and setose 

 tubercles, placed transversely. It is found in June ; it walks very 

 slowly, and falls from the leaf upon being disturbed, rolling itself into 

 a circle. It assumes the pupa state in June, having the body curved ; 

 and the beetle appears in about three weeks.* (De Geer, Mem. 

 vol. v. pi. 8. fig. 27 — 31., and Rosel, Ins. Belustig. vol. ii. class 3. t. 5.) 



The larva {fig. 4:6. is.) of G. nymphaea; is more elongate, having 

 the segments wrinkled, and with lateral tubercles only. I have reared 

 this species from larvae found in company upon aquatic plants in 

 Horningsea Fen, Cambridgeshire. The pupa is attached to the 

 leaves, upon which the larva feeds : this state lasts eight days (De 

 Geer, 3It7n. vol. v. pi. 10. fig. 1 — 6.). These larvae are very sluggish, 

 although furnished with an anal tubercle, which is used as a seventh 

 leg. 



Bouche has described the larva of G. viburni {Naturgesch. p. 205.), 

 which is found upon the Viburnum opulus in May. Another species, 

 G. calmariensis, is exceedingly prolific ; it inhabits the elm, and in 

 certain seasons it is so abundant that it completely defoliates the trees. 

 This was especially the case in the summer of 1837 at Sevres, near 

 Paris, where M. Audouin directed my attention to its effects upon the 

 elms. (See also Mr. Spence's observations on elm insects in the 

 Arboretum LSritannicum.) M. Audouin has observed that the eggs 

 are arranged in two or three rows together along the ribs of the leaf, 

 and are fixed by one end, being of an oval form. 



* In .June, 1833, the pasturage of Mount Jura was greatly devoured by the larva 

 of this insect, which occasionally appears in vast numbers. {Ann. Soc. Ent. de 

 France, 1834, p. 19.) Some observations, in illustration of the occasional appear- 

 ance of this insect in great profusion, are noticed by Mr. W. W. Saunders, (Ent. 

 Trans, vol. i. p. 33.); an innumerable quantity having been observed dead on the 

 coast of Lincolnshire. 



