SCIENCE-GOSSIP. 



[Feb. 1, 1865. 



completes its growth about the month of 

 October or November, It now prepares for 

 its first metamorphosis by ceasing to eat, and 

 thus completely emptying its digestive tube ; 

 then it seeks the hollow of some tree, or hole 

 in some neighbouring wall, and having found 

 a suitable spot, it begins its preparations. 



Unlike the silkworm, this caterpillar spins 

 no cocoon for its concealment and protection, 

 but undergoes its metamorphosis in the open 

 air. It now commences covering the spot it 

 has chosen with filaments which cross each 

 other in every direction ; and this silken 

 couch, delicate in texture, but withal of con- 

 siderable strength, serves as a solid and firm 

 support for the hinder limbs. Then bending 

 its tiunk and head posteriorly almost to the 

 middle of the back — like an acrobat who 

 makes a hoop of his body — it fixes a thread 

 first on one side and then upon the other, 

 and continues the operation till it has formed 

 a kind of girth, composed of about fifty fila- 

 ments. This done, it straightens its body, 

 and undergoes its last moulting ; the animal 

 however which emerges from the cast-off skin 

 is no longer a caterpillar, but a chrysalis, 

 which is sustained horizontally by the hook- 

 lets of its tail and the girth we have de- 

 scribed. 



The Pieris in the new condition which it 

 will maintain during the wintei', bears hardly 

 any resemblance to the caterpillar. The skii), 

 which is dense and hornj^, is covered with a 

 sort of varnish, thrown out at the moment of 

 the metamorphosis, and rapidly dried. It 

 has now assumed an ashy hue, picked out 

 with black and yellow. The body has be- 

 come thicker, but, as it were to compensate 

 for this inci^ease, has been shortened by about 

 one-third. Instead of being made up of 

 rings from end to end, it now exhibits two 

 principal segments. The hinder one alone, 

 which is short and conical, presents the 

 annulose condition, although there is a keel- 

 like elevation upon the dorsal portion of 

 the anterior segment, and a kind of crest 

 upon its undersurface. The head and feet 

 seem at first sight to have disappeared 

 altogether. On closer examination, hov/ever, 

 we can detect a series of rounded elevations 

 and ])rojections, arranged symmetrically. 

 Knowing what this inert mass will even- 

 tually become, we can almost fancy that we 

 see the various organs beneath the skin, or 

 rather beneath the cement which invests it ; 

 the proboscis, antenna, and wings being indi- 

 cated in the same nianner as the form and 

 [.ropoitions of a mummy are rudely mapped 

 out by the bandages which enshroud it. To 



all intents and purposes the chrysalis is a 

 mummy. 



About the middle of spring, or beginning 

 of summer, the Pieris undergoes its second 

 metamorphosis. Its envelope splits along 

 the dorsal portion, and the organs which had 

 been iiiclosed by the crests and elevations 

 come out, as if from a case ; then the entire 

 animal disengages itself, and from the chry- 

 salis coffin there emerges a perfect butterfly. 

 At first its feet are of too pliant a character 

 to support the body ; the wings are heavy, 

 thrown into microscopic zigzag folds, and 

 unlit for flight; and the proboscis with its 

 component halves often separate, is extended 

 in a right line. But after a while the sur- 

 rounding liquids are evaporated, the limbs 

 are strengthened, the proboscis is adjusted 

 and coiled up, the wings are unfolded, and 

 the insect, which in its early days was "a 

 creeping thing," and afterwards a motionless 

 one, flies to the nearest flower and makes its 

 first repast. 



VARIATIONS IN BRITISH PLANTS. 



1HAVE here set down a few examples of 

 variation which have come under my notice 

 during the last two or three years. I hare 

 observed that the species contained in the 

 order Eanimculacece have a peculiar tendency 

 to depart from their ordinary forms ; and 

 many instances of such variations occur iu 

 the earlier numbers of the Naturalist. In 

 addition to those therein recorded, I may 

 mention that I have observed in Brompton 

 cemetery a curious variety of the Bulbous 

 Crov/foot [Ranivncalus hulbosus), which bears 

 flov\^ers of apale yellow or cream colour; though 

 it differs in no other respect from the tj^pical 

 form ; this variety is apparently constant, 

 about a dozen examples having been observed 

 iu the same spot for the last four or five 

 years. A friend has observed a single plant 

 of the same species, at High Wycombe, Bucks, 

 having blossoms "as double as those of the 

 Dahlia," the whole of the stamens being trans- 

 formed into petals. Another . species, the 

 Creeping Crowfoot {R, rejjens) is peculiarly 

 variable in the relative number of stamens 

 and petals ; and semi-double varieties are in 

 some places equally common with the ordinary 

 form. The Lesser Spearwort (P. Flamnnda) 

 also occasi(uiaiIy exhibits a similar peculiarity. 

 The singularly deformed petals of the Wood 

 Gtov/foot (/?. auricomus) must be familiar to 

 all who know the plant; regularly shaped 



