NOTES ON PIERIS MANNl, MAYER. 71 



rapae. P. rapae attains on an average a greater size than P. vianni. 

 The following distinctions were observed with microscope : — 



Pieris rapae (5th instar) : Primary tubercles white with a a jet-black 

 hair, and of about the same size as the largest black points. 

 These points are shiny black, each terminating in a light (whitish) 

 hair. There are, besides, numerous very small black points, many of 

 which bear a short whitish hair. The black points have not a suffused 

 black patch at the base. Spiracles oval, nearly white, with a 

 raised, shiny, black border. 



Pierh manni (5th instar) : Primary tubercles white, tipped with 

 black, on abdominal segments, much suffused with black on thoracic 

 segments. They are smaller than in rapae. Each one carries a 

 black hair. The large black points are much lar<je.r than the pritnary 

 tuberclea. They have light grey, or nearly colourless, hairs, coarser 

 than those of rapae. Each one has a diffused black stain around the 

 base, more particularly on abdominal segments. The small black 

 points are also larger than in rapae, and have often dark base stains. 

 Spiracles oval, light brown, with a raised, shiny black border. The 

 white primary tubercles are very conspicuous in rapae under micro- 

 scope, butnot easy to see in manni owing to the smaller size and much 

 larger area of black at tip. In both species the hairs appear often to 

 terminate in a very small knob. 



The Pupa is smaller in manni, 16-5mni. minimum to 19mm. maxi- 

 mum total length. I have pupte of P. rapae ranging from 16mm. to 

 21mm. Average about 19mm. Shape of /'. vianni less angular than 

 that of /'. rapae. The thoracic crest is more rounded, not rising to 

 such a high sharp point. The pointed projections of the lateral ridge 

 on 2nd and 3rd abdominal segments are lower and less thorn-like. 

 Abdominal ridge similar in shape and development. Nosehorn shorter 

 and entirely pale grey excepting a very faint dusting of black specks 

 on the sides. P. rapae has a very definite black streak along each 

 side of nosehorn, which I have never seen in manni. The absence of this 

 streak enables one to identify a pupa of manni at a glance. The pupa 

 (grey form) is pale grey in manni, the grey having a slight greenish 

 tint on appendage-cases. In colour and spotting it is much like a 

 diminutive l\ brassicae pupa, as before stated. P. rapae pupa is of a 

 pale brownish-grey, quite distinct in colour from P. manni. The 

 arrangement of the black spots is similar in both species, but in 

 rapae they are often smaller, and, as a rule, many are missing. The 

 microscopical black specks connected with the skin-pitting are frequently 

 denser about the thorax and wing-cases in rapae than in manni, some- 

 times showing as a suffused mottling. I do not wish to convey by 

 this statement that there are, in this case, more skin-pits than usual, 

 but merely that the spots staining them are larger and darker than in 

 general. The light green summer form of the pupa is common to 

 both species. As with the grey winter form, the shape makes it easy 

 to separate them, while the presence or absence of the black streak on 

 the nosehorn is always a good distinction. A small number of P. rapae 

 and P. manni larvge reared in August all gave light green pupag, but 

 no doubt the grey form also occurs in summer, under certain con- 

 ditions. The green form apparently is not met with in autumn, but I 

 have one specimen of P. rapae of an intermediate form. Collectors 

 who have series of P. rapae from France would do well to examme 



