99 



External Morphology 



The most important work on pupal morphology has been done by 

 E. B. Poulton and Dr. T. A. Chapman. Poulton ('91) in his paper 

 on the "External Morphology of the Lepidopterous Pupa" discusses 

 a few pupal structures but does not attempt to name all of the parts 

 or to locate any of them. So far as known he was the first to point 

 out that the piipal structures were more than cases for the imaginal 

 structures and objected to the terms pterothecae, ophthalmothecae, etc., 

 as applied to pupae. Believing that Poulton's theory is correct, such 

 terms have not been used in this discussion, nor the terms wing cases, 

 antennal cases, leg cases, etc., but these are spoken of simply as wings, 

 antennae, maxillae, etc. Chapman's papers, already referred to, dis- 

 cuss very fully some of the structures and describe their exact loca- 

 tion; but as they include only a few figures one is left very much in 

 doubt as to the identity of many of the structures and their location. 

 W. Hatchett Jackson ('91) published a very valuable paper on the 

 "Morphology of the Lepidoptera" in which he discussed the external 

 determination of sex in the pupa. A short discussion of the chrysalis 

 was published by Dr. S. H. Scudder ('89), and some of the parts were 

 named. In a paper previously cited, Dr. A. S. Packard ('95) gives 

 many figures of pupae and names the parts, but his homologies are 

 far from correct. It seems necessary, therefore, before proceeding 

 further, to discuss the principal pupal structures and indicate their 

 location by means of figures. 



The homologies given in this paper were determined by a series 

 of dissections of pupae in various stages of development, the preimago 

 being found most valuable for this purpose. Pupae of nearly every 

 family mentioned in this discussion have been studied in this way, be- 

 ginning with the Microptervgoidea and extending through the He- 

 pialoidea, Cossoidea, and other generalized families, including the 

 Saturnioidea which are believed to be the most specialized of lepidop- 

 terous pupae. The change from larva to pupa has been watched in 

 many species and the subsequent folding and soldering down of the 

 appendages carefully noted. A large number of species have been 

 bred and a study of the method of dehiscence, as shown by the pupal 

 skin, has thrown considerable light on many instances where there 

 was doubt as to the number of free abdominal segments, or where a 

 suture was obscured by folds or other modifications of the integument. 



The three regions of the body — head, thorax, and abdomen — are 

 easily recognized, and each will be discussed in turn. There occur, 

 on all of the regions of the body, in different families prominent pro- 



