246 THE FERTILISATION OF FLOWERS. [PART IIL, 
styles. First the four outer ones, which stand opposite the sepals, 
ripen one after the other, and then the other four. All the stamens 
dehisce on both sides, and flap open so widely that they are covered 
almost all round and also above with pollen. The stigmas are 
susceptible of fertilisation during the whole time of flowering. A 
number of such flowers, from five to upwards of a dozen, are closely 
packed in an almost level cyme, and, together with the broad green 
bracts that lie nearly in the same plane, form a conspicuous expanse 
with a golden-yellow centre. 
Numerous minute insects of different orders are attracted. 
Most of them touch a stigma with one part of their body, and with 
another one or more of the anthers; and so cross-fertilisation is 
promoted. But self-fertilisation is not unfrequently induced by the 
tiny guests that creep irregularly about the flower. In default of — 
insect-visits, self-fertilisation can only take place in a perpendicu- 
lar or nearly perpendicular position of the flowers; fur ouly then 
can pollen fall.upon the stigmas. On April 13, 1872, I collected 
forty-six insects upon flowers growing in the shade. 
A. Diptera—(a) Muscide: (1) Five specimens of Sciomyza cinerella, 
Fallen ; (b) Simulide: (2) Simulia sp., three specimens ; (c) Cecidomyide : 
(3) Six specimens ; (d) Mycetophilide : (4) Five specimens ; (e) Chironomide : 
(5) Three specimens, besides minute species. B. Hymenoptera—(a) Formi- 
cide: (6) Lasius niger, L. §, eight specimens; (7) Myrmica ruginodis, 
N. & (t), two specimens; (8) M. levinodis, N. %, three specimens; (d) 
Cynipide : (9) Eucoila, Westw. (Cothonaspis, Hart.), one specimen. C. Cole- 
optera—(a) Phalacride : (10) Olibrus zeneus, F. one specimen ; (b) Lathridii : 
(11) Corticaria gibbosa, Hbst., two specimens ; (c) Curculionide: (12) Apion — 
varipes, Germ., four specimens ; (13) A. onopordi, K., three specimens ; all the 
visitors were licking honey. 
Also, I found small snails (young Succinee) upon many flowers, — 
either creeping about, or devouring the stigmas or anthers. In the 
slimy matter left upon the flowers, pollen-grains could as a rule be 
recognised : in several cases I could distinctly see that pollen was 
placed upon a stigma by help of the snails. 
Now if, under some changed conditions, insect-visits altogether 
failed, it would obviously be of advantage to the plant to have 
cross-fertilisation promoted by the snails, at least on the supposition 
that by new modifications the ravages of the snails should ke 
obviated. This example may explain the origin of such a floral 
arrangement as Delpino observed in Alocasia odora and Rhodea 
japonica. And so the doubt which I formerly published concerning 
the truth of Delpino’s theory is now removed, 
/ > 90> uel sme tall 
