384 THE GROUSE IN HEALTH AND IN DISEASE 



The anterior half of the body becomes gradually stouter, and 

 the larva adopts the peculiar and interesting habit of suddenly 

 straightening itself and then reassuming the horse-shoe form. 

 In course of time, by this means, the skin of the dorsal surface 

 of the three segments behind the head splits, and the emergence 

 of the pupa is gradually effected by wriggling. This process, 

 as observed by Mr Grimshaw in favourable circumstances, may 

 be accomplished in twenty minutes, but may also take an hour 

 or even more. 



The pupa, when newly emerged, is of a creamy white colour 

 throughout, with the exception of the tiny bristles about to be 

 mentioned, which are blackish. The characteristic form of a 

 Chrysomelid beetle is now distinctly traceable, while the legs, 

 wing-cases, antennae, and even mouth-parts can be recognised. 

 Seen from above, the hemispherical thorax (prothorax of the 

 mature beetle) occupies the most anterior portion of the body, 

 and carries about a dozen tiny bristles, four of which form a 

 curved row near the posterior margin, and the rest a row near 

 the anterior margin. In a dorsal view the head is quite invisible. 

 The meso- and meta-thoracic segments, and those of the abdo- 

 men, are each provided with a row of four bristles, which are 

 about equidistant from each other. Laterally, below the level 

 of the spiracles, the abdominal segments are each tipped with 

 a tiny bristle. Seen from beneath (see PI. xxn., Fig. 4) the 

 pupa shows distinctly the legs folded up close under the body, 

 and the antennas beautifully curled under the two anterior pairs 

 of legs and brought out again so as to show the tip of each 

 close to the four anterior tarsi. Most of the joints of the legs 

 may be distinctly seen, the posterior pair being folded beneath 

 the wing-cases, which are bent round from the dorsal surface 

 of the pupa and do not nearly reach the end of its body. 



The first change to be noticed in the pupa is that on the 

 fifth day after emergence the eyes begin to change colour, 

 assuming a pale brown tint, while a couple of days later they are 

 O f a more distinct brown, and the separate facets may be dis- 

 tinguished. On this day also (the seventh) the extreme tips of 



