THE EXTERNAL MORPHOLOGY OF THE LEPIDOPTEROUS PUPA. 55 



there is a separate opening into the bursa copulatrix. Copulation would 

 be almost impossible if the female aperture were placed on the apex of a 

 conical process ; hence the necessity for a more accessible aperture. This 

 arrangement having been once set up, would be retained after the disap- 

 pearance of the necessity under which it originally arose, because of 

 the many co-adaptations which would have been entailed in both sexes." 



Poulton further writes : " There are two distinct generative open- 

 ings in female pupae — an anterior for the bursa copulatrix, and a 

 posterior for the oviducts. The anterior is probably always associated 

 with the 8th abdominal, it is more distinct than the other, and is 

 usually provided with prominent lips. It is often slit-like, and extends 

 from the posterior to the anterior boundary of the segment, but is 

 especially dilated at its posterior end. In a single individual of 

 Notolophus antiqua it appears to be placed on a forward extension of 

 the 9th abdominal into the 8th, but in another individual of the same 

 species its position is normal. We may safely conclude that the 

 anterior generative opening is associated with the 8th abdominal seg- 

 ment. The segmental relation of the posterior generative opening is 



far more difficult to determine In some examples, the 



posterior aperture is placed on the 9th abdominal immediately in front 

 of, but distinct from, the apex of the median prolongation of the 10th 

 abdominal. In others, the aperture is placed on the apex of the pro- 

 longation itself, and, therefore, belongs to the 10th abdominal seg- 

 ment. In the majority of pupa?, the opening occurs at the apex and 



may or may not be considered to belong to it Whether 



connected with the apex or not, the aperture is always placed close to 

 it. The posterior generative opening is often obscure and unrecog- 

 nisable on the surface and is often fused with the anterior aperture. 

 Even when the two openings are fused, and are prolonged into a 

 common invagination, the double nature of the latter is shown by a 

 furrow. The posterior opening may be surrounded by prominent lips 

 or by a swollen margin, or it may be without these features." This 

 observer further notes that although the female organs are not asym- 

 metrical like those of the male they are subject to even greater 

 individual differences ; also that the pupae of Ehopalocera possess 

 essentially similar openings, but they are much more difficult to 

 interpret, because of the specialisation in shape and the amount of 

 surface sculpture. The ventral area of the 9th abdominal may be 

 entirely hidden, e.g., Nemcobius lucina and Anjynnis ar/laia (which is 

 so hooked round ventrally, that the ventral surfaces of the abdominal 

 segments are almost obsolete), but Rhopalocerous pupae that show the 

 organs distinctly prove that both the male and female organs are, in 

 the butterflies, essentially similar to those of the Heterocera. 



Jackson refers the posterior aperture to the 9th abdominal segment 

 and writes : The female sex is to be recognised by the aspect of the 

 sternal regions of the 8th and 9th somites. There are typically and 

 primitively two linear depressions, one in each of the sternal regions 

 named, but they may be hidden or become confluent. These 

 depressions coincide respectively with two pairs of vesicles invaginated 

 from the hypodermis. The following types of structure may be dis- 

 tinguished : — 



(1) A short fine longitudinal line surrounded by an oval and slightly raised 

 area, on each of the 8th and 9th sterna — Pieris. 



