248 THE FERTILISATION OF FLOWERS. [PART ITI. 
honey in two shallow depressions on its inner side, leaving it 
fully exposed. Above it gives off seven to eighteen yellow, knobbed, 
glandular bodies, which surround the upper portion of the ovary 
and are probably of service in making the nectaries more obvious 
to flies which alight in the middle of the flower. | 
These yellow knobs placed at the ends of the hairs look so 
exceedingly like drops of fluid that it needs special examination 
to convince one that they are perfectly dry. An observation of 
my son Hermann’s proves that even flies are deceived by this 
appearance ; he observed from a very short distance a specimen 
of Eristalis nemorum trying to lick these bodies for a long time, 
until at last it flew away on his coming closer. 
We have thus in Parnassia palustris a very well-marked 
example of a deceptive flower, which deludes the foolish flies by 
displaying a multitude of conspicuous but sham drops of honey ; 
and which, after thus alluring them, affords them indeed some 
easily accessible honey, which repays their trouble but is quite 
incommensurate with the apparently bountiful display. The 
smaller flies generally travel round the flower, to reach all the 
nectaries ; the larger ones rest in the middle of the flower for this 
purpose, and so dust their under sides with pollen in younger 
flowers and accomplish cross-fertilisation on passing to older ones. 
Visitors: A. Diptera—(a) Syrphide: (1) Eristalis nemorum, L., s. ab. ; 
(2) E. arbustorum, L., s. ab. ; (3) Helophilus floreus, L., s. ab. ; (4) Syrphus ; 
ribesii, L., s. ab. ; (5) S. balteatus, Deg., very ab., s.,{sometimes f.p.: (6) S. 
pyrastri, L. ab. s.; (7) 8. excisus, Zett, s.; (8) Melanostoma mellina, L., s. ; 
(9) Melithreptus scriptus, L., s.; (10) M. menthastri, L., s. ; (11) M. teeniatus, 
Mgn., s.; (12) Syritta pipiens, L., ab. s.; (b) Muscide: (18) Sarcophaga — 
earnaria, L., s.; (14) Pollenia vespillo, F., s.; (c) Tipulide: (15) Tipula — 
oleracea, L. B. Hymenoptera—(a) Tenthredinide : (16) Tenthredo sp., s. ; 
(b) Ichneumonide : (17) Many small species, s. ; (c) Sphegide: (18) Pompilus — 
viaticus, L.; (19) Gorytes campestris, L, C. Coleoptera—(20) Coccinella — 
7-punctata, L. ; (21) C. 14-punctata, L., both very ab., 1h. A list of Alpine 
visitors (including 43 Diptera) is given in No. 609. 
Tribe Hydrangee. 
Philadelphus coronarius, L., is proterogynous. When the flower — 
opens the stigmas are already ripe, but the stamens still immature. 
In weather favourable for insect-visits, it is easy to find flowers — 
whose anthers are still closed but whose stigmas are sprinkled — 
with pollen. The numerous anthers stand, both before and after 
dehiscence, close round the stigma, some on a level with it, some 
higher, some lower; the outermost dehisce first, the innermost 
last ; all cover themselves all round with pollen. Honey is secreted 
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