Myrmeleon formicarius from the Pupa. 57 



judging by the clean manner in which G. clathrata bad 

 opened its cocoon by a circular lid, these jaws must be 

 very eflficient instruments for effecting this operation. 



[Note on the pupal mandibles by Dr. Chapman. — " In 

 the three stages of J/, formicarius the mandibles are of 

 interest to me in connection with the ancestry of the Lepi- 

 doptera, in view of the considerations I advanced in Trans. 

 Ent. Soc. 1896, p. 568. No doubt any common Chrysopa 

 or Hcmerolms would afford a similar series, but I am not 

 aware of such a series being figured, certainly not in any 

 English medium I have come across. The pupal jaws are 

 modified so as to be specially suited for opening the 

 cocoon. The pupa throughout its whole existence is 

 absolutely quiescent, and these jaws rest unused. It is 

 Avhen the insect is no longer a pupa, but an imago within 

 the pupal skin, that it becomes active and uses these jaws 

 to open the cocoon. It is not the pupa, but the imago 

 that does this, these pupal jaws being merely a sort of 

 glove to the marginal jaws, now fully developed, but no 

 doubt like the wings requiring a few minutes' adjust- 

 ment to the new conditions, when the pupal skin has been 

 cast off. Mr, Lucas' specimen shows the pupal skin left 

 in the grip of the opening made in the cocoon, the imago 

 leaving it as soon as the anterior portion is outside the 

 cocoon. It is easy to understand how these pupal jaws 

 are moved by the imago, since it has its own jaws inside 

 them ; but how the similar jaws that are used for the 

 same purpose by the Trichoptcra.- and the Eriocraniadm, 

 which have no imaginal jaw'S at all, are energised by the 

 imago, remains as difficult to understand as I found it ten 

 years ago."] 



