I 1830.] 153 



■oblong-ovate form, of a dirty greenish-white colour, with numerous 

 black scaly spots ; its meso- and metathoracic segments are furnished with 

 two large lateral, conical tubercles, and the abdominal segments have also 

 two rows of smaller dorsal and lateral tubercles, from which . . . drops 

 of a fetid fluid are emitted when the larva is alarmed." The Chryso- 

 mela larva, on the other hand, has the same general resemblance to 

 that of Timarcha, as figured by "Westwood {op. cit., p. 389, fig. 48, 2). 

 The larva of Gastrophysa moults twice before pupation, retaining the 

 same larval form. Chrysomela moults three times : before the first 

 moult the young larva is hirsute, but afterwards nearly smooth, without 

 hairs, or with only a very fine pubescence, and without warts or 

 tubercles. The Gastrophysa larva is always depressed and extended : 

 that of Chrysomela laterally compressed, with the manitrunk and ab- 

 domen humped — rising from the darker scaly head and prothorax in 

 the manner of the shell from the snail in crawling. Before the first 

 moult the larva, with its arched hairy back and conical ear-like antennae, 

 is often ridiculously like a young kitten. In all these points — character 

 of shell,* number and arrangement of eye-spots, and dorsal warts, 

 number of moults and general anopluriform appearance — the larva of 

 Prasocuris marginella agrees with Gastrophysa and differs from Chry- 

 somela. 



One other point of interest remains to be mentioned, a point 

 of agreement between Gastrophysa raphani and Lina populi. At 

 pp. 242 — 3 of vol. ii, Kirby and Spence, speaking of osmateria, say : 

 I The grub of the poplar beetle (Chrysomela populi) also is remarkable 

 for similar organs. On each side of the nine intermediate dorsal 

 segments of its body is a pair of black, elevated, conical tubercles, of 

 a hard substance ; from all of these, when touched, the animal emits 

 a drop of a white milky fluid, the smell of which, De Geer observes, 

 is almost insupportable, being inexpressibly strong and penetrating. 

 These drops proceed at the same instant from all the eighteen scent- 

 organs ; which forms a curious spectacle. The insect, however, does 

 not waste this precious fluid ; each drop instead of falling, after appear- 

 ing for a moment and dispensing its perfume, is withdrawn again within 

 its receptacle, till the pressure is repeated, when it reappears." See also 

 plate xviii, fig. 1. I wish to call attention to the sentence I have 

 underlined, for a reason which will be immediately apparent. I wish, 

 in fact, to ask : is it quite certain that this emitted matter is entirely 



* The nature and amount of the glutinous matter is not obvious in the case of Prasocuris 

 eggs. The insect cuts a small round hole in the hollow petiole of a Rarmncutus leaf and deposits 

 the eggs, to the number of I or 5—7 in the interior. —J. A. O. 



