^DURATION OP THE PUPA STATE. 215 



the larva ; but this, as I have already said, is certainly in- 

 acciu-ate, as I have proved by direct observation, and as is 

 further evidenced by the leg-bearing structure of the first 

 segment in many larvae. The loss must therefore occm* in 

 the abdominal segments ; but upon this branch of the sub- 

 ject we require more direct investigations than have yet been 

 devoted to its elucidation. As regards the segmental de- 

 velopement of the earwig, in which the male has nine and 

 the female apparently only seven abdominal segments, I have 

 published a memoir in the Transactions of the Entomological 

 Societ}'^, proving that the loss in the latter six occurs in the 

 penultimate and antepenultimate segments of the abdomen. 



Pupae, in general, are of a dirty white colour when their 

 situation is vmder ground, or in cases artificially constructed 

 by the larvae. Those, more especiall}^, which lie naked under 

 ground, are of a dark bright bro\Mi, whilst those which are 

 naked, and exposed to the action of the light, are more 

 variable in their tints, some being gilded, as in the aureliae, 

 or chrysalides of butterflies. 



The period passed by insects in the pupa state is very 

 variable, the variations extending from a few days to as 

 many years. Ordinarily, its extent is determined by the 

 circumstances to which I have alluded in my observations 

 upon the duration of the larva state — that it is chiefly de- 

 pendent upon the temperature of the atmosphere. Provi- 

 dence has wisely ordained that the developement of the 

 perfect insect shall not take place until the season when 

 proper food for its ovm sustenance is at hand, or a proper 

 situation for the deposition of its eggs is to be discovered. 

 Hence some insects are produced earlier, and others later, 

 in the season ; and in double-brooded species, or those of 

 which there are two generations in a year, the early brood 

 passes but a very short time in the pupa state, whilst the 

 later brood remains throughout the winter as pupae. Hence 



