122 OUR HOUSEHOLD INSECTS 



the third not till the end of the year. There would 

 appear to be seven moults in all before the fully 

 developed form is attained, but after the first three, 

 these are made only annually. This, at least, is the 

 conclusion arrived at by Cornelius from observations 

 made on captive cockroaches; but it may be open to 

 question whether the course would have been precisely 

 the same under more natural conditions, and, unfortu- 

 nately, no other observations have been recorded on this 

 particular species. 



If, however, the above results represent the usual 

 state of things, cockroaches are certainly gifted with 

 extraordinary longevity, for their life evidently extends 

 over a period of at least five years. One is accustomed 

 to think of insects as truly ephemeral creatures, and it is 

 probable that the majority of them do not require more 

 than a single twelvemonth to complete their cycle of 

 existence ; where the preliminary stages occupy a longer 

 time than this, the species chiefly feed in concealment, 

 as buried in the ground, like the grubs of the cock- 

 chafer, or in solid wood, like those of the stag-beetle. 

 The experience of Sir John Lubbock with his ants has, 

 it is true, demonstrated that the life of insects may, 

 under favourable conditions, last much longer than we 

 should have expected. Some of his ants lived with him 

 upwards of eight years ; but these were in their perfect 

 condition all that time, and their early life and periods 

 of transformation and growth had been, as usual, rapidly 

 accomplished. Cockroaches, on the other hand, if the 

 above results are to be accepted, take a long time to 

 pass through their introductory stages, but we have no 

 evidence at all as to how long they live after becoming 

 full grown. To so active an insect, the dangers and 

 possible mischances of a long larval life would necessarily 



