Insects. 1 795 



egg is the last act prior to closing the cell, and the foetal larva of Sty- 

 lops which we may reasonably enough suppose left in the nest by the 

 passing and repassing of the bee, must remain for some days without 

 food, or must devour a portion of the pollen or honey stored for the 

 larva of the bee. 



However this may be, it soon undergoes an important transforma- 

 tion, analogous to that which I have characterized as the foetal meta- 

 morphosis of Crustacea; that is to say, on undergoing its first ecdysis, 

 it assumes a normal form and habit ; and I consider it desirable that 

 I should, in a pointed manner, invite the attention of entomologists to 

 this peculiar metamorphosis in the larva of Stylops which I term 

 fcetal, for it is of great moment in the present enquiry, and furnishes 

 us not merely with the means of clearing up a formidable difficulty in 

 the history of Stylops itself, but at the same time furnishes us with a 

 most valuable clew to its affinities, for it will be seen in the sequel 

 that the larvae of other insects possess a foetal metamorphosis, and that 

 such larva) present also very obvious structural affinities to that of 

 Stylops. The larva, with its first skin, sheds also its legs, and be- 

 comes perfectly, or at least apparently, apod ; it pierces the soft thin 

 skin of the bee-larva, enters the interior and feeds on its juices, like 

 the ichneumon-larva in the caterpillar of a butterfly, without attack- 

 ing any vital part or causing its supporter any serious injury. Dr. 

 Siebold, to whom we are indebted for the major part of these interest- 

 ing discoveries, informs us that, in its transformed state the Stylops- 

 larva appears to have a distinct mouth and jaws, a simple coecal intes- 

 tine, and that he could discover no anal aperture. The number of seg- 

 ments is now reduced to nine, the four anterior ones being united, and 

 forming a single large and square segment, which he calls the cepha- 

 lothorax : in this state Dr. Siebold adds, that he could readily dis- 

 tinguish the males from the females, the cephalothorax of the males 

 being arched and conical, and the telum or last segment straight and 

 pointed; whereas in the females the cephalothorax is rounded or 

 truncated, and the telum is large and rounded. The position of this 

 larva is described by Jurine, who informs us that the anus or telum is 

 fixed between the segments of the bee's abdomen when that insect 

 has reached the imago state, and that the head is directed towards 

 the thorax of the bee. It is right in this place also to observe, that 

 Jurine, and other competent observers, have failed to discover the 

 mouth, so confidently spoken of by Siebold. Under these circum- 

 stances, no stress will be laid either on the absence or presence 



