PIERIS RAP.E, L., AND P. MANNI, MAYER. 149 



Pieris rapae, L., and P. manni, Mayer {with plate). 



By PROFESSOR J. REVERDIN, M.D., Memb. Lep. Soc. Gen. 



The interesting articles by Messrs. Powell and Harrison, printed 

 in the Ent. Record, have clearly demonstrated that these two Pierids 

 differ in certain constant characteristics and that they should, therefore, 

 be considered as distinct species, a conclusion already arrived at by 

 Count E. Turati in his delightful study on P. majuii and its variety, 

 or rather summer form, rossii, Stefanelli. It seems to me that an 

 anatomical study of certain organs confirming this conclusion should 

 not be void of interest. I have, up till now, only examined the male 

 genital organs and the androconial scales with the following results. 



Male Genital Armature: In the first place I noted a slight differ- 

 ence in the size of the armature, that of P. rapae being rather larger 

 than that of P. wauni. The uncus is practicall}' the same in the two 

 species ; immediately behind its base, attached to either side, stretches 

 a slight ellipse-shaped membrane ; this membrane is rather larger in 

 P. rapae than in P. manni. The saecus of P. manni is more regularly 

 formed and is shaped exactly like a thimble. The difference between 

 the clasps is more considerable and was constant in every preparation 

 that I made ; it is easier to seize this difference by a glance at the 

 accompanying plates than by reading my description. Whereas, in 

 the case of P. rapae (pi. xiii., fig. 1), the outline of the clasp may be 

 called a regular curve with its convex and concave parts united in- 

 sensibly, the outline of that of P. manni (fig. 2) is, so to speak, 

 harsher ; the extremity of the clasp runs to a point and its upper 

 surface presents an abrupt protuberance almost entirely absent in 

 P. rapae. 



The difference between the two armatures was striking enough to 

 enable me to distinguish at a glance to which of the two butterflies 

 the preparations I was examining belonged. 



I have only been able to examine the armature of a single rossii, 

 and found it absolutely identical with that of manni. 



Androconial Scales: The distribution of the androconia seems to me 

 the same in the two species; they are all situated on the upper surface of 

 the wings and are in greater abundance on the fore- than on the hind- 

 wings ; the regions of the discoidal cell and of the apical spot seem 

 particularly well provided with this class of scales. The scales were 

 drawn by my colleague, Mr. Jullien, to whom I am also indebted 

 for the photographs of my preparations. While the drawings show 

 that these scales are nearly the same in the two species it may be 

 noted that : (1) The androconial scales of P. rapae are larger than 

 those of P. manni. (2) Their outline is more regular and symmetrical, 

 drawn, so to say, with greater elegance in the case of P. manni. 



These points of difference have been constant in every preparation 

 I have made. The androconial scales are represented by the upper 

 three of each figure. Below them are given the ordinary scales and a 

 careful examination of the latter seems to point to a greater regularity 

 in the case of P. manni ; the curved outline leading to the pedicel is 

 notably more symmetrical in P. manni, more irregular in P. rapae. 



It is evident that the examination I have made ought to be repeated 

 on a larger scale and that a study should be made of the internal, as 

 July 15th, 1909. 



