SCIENCE- GOSSIP. 



H.w. strongly tinged with ochreous-yellow. U.s. 

 $ and ? , f.w. with a large black irregular spot 

 reaching from the level of disc, cell to in. marg. 

 and crossed by white nervures. Apices yellow. 

 H.w. bright ochre-yellow, dusted with black. 



Hab. Canary Islands, coast of Teneriffe (Mrs. Holt 

 White, in " Butt, and Moths of Teneriffe," p. 29), 

 Orotava (R. H.). I have received many specimens 

 from the last locality taken by Don Ramon Gomez. 

 IV— IX. 



Larva. "The larva is smooth, has a ground 

 colour of grey, finely dotted over with black spots. 

 There is a yellow stripe on the back and along- 

 each side. It feeds on the nasturtium (Tropaeoluvi) 

 gregariously." — " Butt, and Moths of Ten." loc. cit. 



This very beautiful and striking Pieris has been 

 thought by some to be merely an insular develop- 

 ment of P. brassicae, the common large-white 

 butterfly of the British Isles. It is very difficult to 

 speak with certainty with regard to insular species, 

 and especially so as P. brassicae does not occur in 

 the Canary Islands, where the form clieirantlti is 



Pieris liippia, 



common. There is another species, the one whose 

 description follows, inhabiting the Canaries and 

 Madeira, that certainly more resembles this than it 

 does P. brassicae. 



11. P. wollastoni Staint. R.H. p. 120. 



50—60 mm. 



Closely allied to P. clieiranthi, but smaller. 

 $ with the black spot on f.w. similar to that seen 

 in the last species. <? has the spots as in P. cheir- 

 anthi, though not so strongly marked. H.w. tinged 

 with yellow above. U.S. of J and $ has the yellow 

 colouring on f. and h.w. replaced by grey, finely 

 powdered with black scales. 



Hab. Madeira, also Teneriffe. 



12. P. brassicae L. Syst. Nat. x. 467. Lg. 

 B. E. p. 28, pi. VI. fig. 2. " The large-white." 



50 — 60 mm. 



"Wings white in both sexes, bases dusky, f.w. 

 tipped with black. 9 with three black spots, two 

 of them nearly circular, placed one aboVe the 

 other, nearly midway between the centre and 

 in. marg. ; the third is triangular, with its apex- 



inwards, placed beneath the other two, and 

 generally touching the lower one. But the three 

 spots are never' coalescent, as in the last two 

 species; neither is there ever in the $ a black 

 spot in centre of f.w. H.w. with a black spot in 

 the middle of the costal border in both 

 U.S. ground colour of h.w. and apices of f.w. 

 greenish, and not, ochreous-yellow (as in /'. 

 clieiranthi). H.w. dusted with black. 



Hab. The entire region; except the Polar 

 portion, the Canaries, and Madeira. Usually a 

 very common species, sometimes occurrinir in 

 abundance, and often migratory. V — IX. 



(To be continued?) 



ON THE NATURE OF LIFE. 

 By Geoffrey Martin. 



I TRUST I may be permitted to answer the 

 courteous criticism of my paper on " Life 

 Under Other Conditions" (S.-G., N.S., vol. vi. 

 pp. 291 and 32G), by Dr. Allen in the May number 

 (vol. vi. p. 365) of Science-Gossip. I substantially 

 agree with Dr. Allen concerning the functions of 

 carbon and nitrogen in living matter, but it appears 

 to me that he devotes too much attention to the 

 nitrogen atom and neglects the carbon. Dr. Allen 

 holds that nitrogen in living matter is the " central 

 or linking element." That it may be a " linking" 

 element in the sense of the " floating linkages " (') 

 of Knarr, I am willing to admit ; but that nitrogen 

 ever forms the " central " element in living matter 

 is more than open to doubt. 



Certainly the chemical facts do not justify this 

 view. The products of the breakdown of living 

 matter seldom, if ever, give evidence of the " cen- 

 tral" position of the nitrogen atom. Indeed, in all 

 such products the '•kernel," or •'core," appears to 

 consist of carbon atoms, and to this " core " the 

 nitrogen is attached. This may be seen by glancing 

 at the formulas given below of some simple sub- 

 stances produced by the breakdown of living 

 matter : — 



XH-C-XH\ 



I 

 CO 



I 



0— NH/ 



I 



Uric Acid, 



(CHA,— CH— CH ,— < — ( -o ] t 

 H 



_ / 



x.(('ii;i.rti_.ivi it 



! 



CH.(MI ,).( 



/ 

 Cll. 



rrr.neii 



If such products re-ult from the breakdown of 

 living matter, it is reasonable to suppose that in 



Vl ) V: li I,: " I Strip," vol. i. p. 56, 



1)4 



