42 N.S. ENTOMOLOGICAL SOCIETY. 



of the Neuroptera have the larval and pupal stages quite similar. In the common 

 Coiydalis coinuta and some other forms many of the pupae retain a considerable por- 

 tion of the traceal gills and lateral filaments, thus making the resemblance even closer. 

 Of course the presence of wings and antennae on the ventral surface of the pupa easily 

 distinguish it but in generalized pupae the wings are comparatively short as compared 

 with the total body length. This resemblance between larva and pupa is quite marked 

 in the more generalized families of any of the orders. One of the most striking differ- 

 ences between the larva and pupa is their comparative length. In generalized forms 

 this length is almost equal, but as specialization proceeds there is more difference, and 

 many of the Lepidoptera have a pupa only one-fourth, or occasionally only one-fifth, 

 the length of the larva. This fact, more than any other, leads us to say that there is no 

 resemblance between the two stages. In pupae where the appendages are free, and not 

 soldered to the body wall, the resemblance to the adult is quite striking. This is not 

 true of the other type where the appendages are fastened to the body wall giving the 

 insect a mummy-like appearance. A careful comparison of larvae and pupae of the 

 same species shows us a number of resemblances overlooked in a hasty examination. In 

 many pupae, especially the generalized forms, the head sclerites are the same, and if 

 there is no change in the type of mouthparts, these will show a strong resemblance. The 

 location of the prolegs of the larva is easily determined from a study of the pupa, as 

 well as that of the most external armature as large spines, tubercles and processes of 

 of all kinds. These are often so distinct as to form good characters in separating 

 genera. 



The literature of entomology shows us that there has been comparatively little 

 investigation carried on regarding the pupal stage. It has usually been regarded as 

 an "interpolated stage" which had little or nothing to do with the life of the insect. 

 The fact that the pupa takes no food has eliminated it from the class of noxious pests 

 with which the entomologist has had to wage war and relegated it to a secondary 

 place in the study of the insect's life history. The majority of papers 

 regarding pupae deal really with the adult wing, either as regards the development 

 of the color pattern, or the tracheation a^ a basis for a study of the wing veins. 

 Other papers deal with the effect of heat or cold on the pupa, but this is primarily 

 to study the coloring of the adult. Some work has been done on the changes taking 

 place in the body during metamorphosis. In this connection there is surely room 

 for more extended investigation and the results should be very much worth while. 

 Morphological and histological studies of pupae belonging to all the orders are badly 

 needed. 



The morphology of the external parts is as yet very imperfectly known. Much 

 of this can be determined by studies of the larva and adult and most of the parts have 

 been homologized thruout the different orders, butsome very interesting puzzles yet re- 

 main. There is nothing known about the pupal eye particularly the part known as the 

 ocellar ribbon by Scudder, (1) which I have referred to as the glazed eye. (2) Whether 

 this marks the location of an ancestral pupal eye which was then functional, or whether 

 even now it may in some instances be able to distinguish between light and darkness, are 

 questions which have never been answered. There are many puzzling things in connec- 

 tion with the spiracles, particularly the thoracic ones which differ markedly from those 

 of the abdomen in many genera of Lepidoptera, and in some of the Trichoptera and 

 Coleoptera. The development of the cremaster in the pupa of Lepidoptera was traced 

 by C. V. Riley and homolcgized with the suranal plate of the larva. There are struc- 

 tures in pupae of other orders apparently homologous with the cremaster where no sur- 

 anal plate is recognized in the larva. The appearance and location of the genital open- 



1. The Butterflies of the Eastern United States and Canada, Vol. 1, p. 28. 



2. A Classification of the Lepidoptera based on Characters of the Pupa. Bull. 

 Ill, St. Lab. Nat. Hist., Vol. XII, p. 24. 



