Hypermetamorphosis 



externally. In the midst of innumerable lit- 

 tle sacs of adipose tissue is buried a thin 

 thread in which we easily recognize the es- 

 sential features of the digestive apparatus, 

 both of the preceding larval form and of the 

 perfect insect. As for the medullary cord 

 of the abdomen, it consists, as in the larva, 

 of eight ganglia. In the perfect insect it 

 comprises only four. 



I could not say positively how long the 

 Oil-beetle remains in the pseudochrysalid 

 form; but, if we consider the very complete 

 analogy between the evolution of the Oil- 

 beetles and that of the Sitares, there is rea- 

 son to believe that a few pseudochrysalids 

 complete their transformation in the same 

 year, while others, in greater numbers, re- 

 main stationary for a whole year and do 

 not attain the state of the perfect insect 

 until the following spring. This is also 

 the opinion expressed by Newport. 



Be this as it may, I found at the end of 

 August one of these pseudochrysalids which 

 had already attained the nymphal stage. It 

 is with the help of this precious capture that 

 I shall be able to finish the story of the Oil- 

 beetle's development. The horny integu- 

 ments of the pseudochrysalis are split along 

 a fissure which includes the whole ventral 

 133 



