PART 111.] THE MECHANISMS OF FLOWERS. 227 
} erect, and even inclined towards one another above, and the 
stamens, which dehisce either on the side towards, or on that away 
| from, the centre, have no room to spread out, but remain closely 
| packed between the styles and petals ; so that an insect may easily 
| insert its proboscis, but scarcely its whole head, between the styles 
and stamens to reach the honey-secreting ring. The accessibility of 
the honey is thus greatly reduced, but at the same time, since 
part of the stigmas come in contact with the anthers, self-fertilisation 
/isinsured. In the event of insect-visits cross-fertilisation is easily 
accomplished ; for the insect often alights in the centre of the 
_ flower, touching the stigmas first, and in bending the head down 
_ between stigmas and stamens the former may easily be dusted with 
pollen from another flower. The much less conspicuous flowers and 
less accessible honey cause insect-visits to be fewer and less varied 
_, than in the case of the bramble; and self-fertilisation is very 
frequently made use of. 
Visitors: A. Hymenoptera—(a) Apide: (1) Apis mellifica, L. $, very 
 ab., both s. and c.p.; (2) Bombus agrorum, F. 2, s., ab. ; (3) B. pratorum, L. 
| 64,8. and cp., freg. ; (4) B. hortorum, L. 9, ep. ; (5) B. senilis, Sm. ?, s. ; 
(6) B. silvarum, L. 2, s.; (7) Andrena nigroznea, K. ¢,s. ; (8) A. albicrus, 
 K. g, 8.3; (9) Halictus sexnotatus, K. 2; (10) H. lucidus, Schenck, $ ; (11) 
_H. nitidiusculus, K. ?, all three sucking; (b) Sphegide: (12) Gorytes 
_ mystaceus, L. ; (c) Tenthredinide : (13) Tenthredo rustica, L. B. Diptera— 
_ Syrphide: (14) Rhingia rostrata, L., s. and f.p. ; (15) Volucella pellucens, L. 
- (Sid.),s. and fp. C. Coleoptera—(a) Dermestide : (16) Byturus fumatus, L., 
devouring the anthers and licking honey ; (6) Cerambycidw: (17) Pachyta 
8-maculata, F., licking honey and feeding on the tissues of the flower, ab. 
in Sid. 
135. Rusus Fruticosus, L. (Blackberry, Bramble).—The flowers 
of the bramble have advantages in several respects over those of 
the Raspberry ; the large petals, spreading out flat, are very con- 
_ Spicuous; and the stamens also spreading outwards leave the honey- 
| ‘ ecreting ring easily accessible, These two characters induce much 
more numerous and varied insect-visits than the Raspberry obtains. 
' The outermost anthers are the first to dehisce, and the stigmas 
Tipen at the same time; and most flowers have been cross- 
_ fertilised before the inner anthers are mature. Insects may alight 
with equal convenience either in the centre or at the circumference 
| of the flower, and therefore come in contact either with the stigmas 
or with the ripe stamens. Only the innermost stamens rise up 
after they have dehisced, to come in contact with the outermost 
| stigmas. 
t z Q 2 
