FERTILIZATION OF FLOWERS BY INSECTS. . Sn 
A second condition which is absolutely necessary to obtain a 
regular and indefectible visit of insects is, that the flowers furnish 
them some substance which is agreeable and of use to them. In 
the more simple cases, for example in Anemone and Clematis,* such 
a substance is the pollen which the insects feed upon, or gather as 
food for their larvæ. In other cases it is not only the pollen whiċh 
is presented to them, but also honey, as in the Ranunculi, the Ros- 
aceæ and many other plants. In still other cases the stamens 
withdraw themselves more or less from the depredatorial action of 
insects which then take from the flowers only honey. This takes 
place in the genera Salvia, Pedicularis, and Iris. ¢ 
* Not all the Anemoneæ nor all the Cl ria, hor- 
ensis, pavoni emorosa, and Hepatica are without nectaries, or to 
so, but in A. probably in all the forms of the subgenus Pulsatilla, the 
r row of stamens show different ness of atrophy, and e ers more or les 
abortive and changed nectaries. As to Clematis, it is true that ge of the spe- 
cies are without honey, at least none a yet been found in pory b . Balearica 
and esy: aaen, the more external filaments are transm ar into real 
intrors ney-bearing receptacles, which Bombi and Sylocope n ae 0 in C. 
integrifolia, although the va v stamens; which are hairy and , have n nec- 
"I is very difficult to determine whether a flower has or has not honey. It is fre- 
quently found where least Petia and sec songs by entirely different organs. I have 
been frequently mistaken in the search. For instance, although I have had oceasion 
for three or four years to study me flower of Cali ha palustris, it is only a ron time 
since I discovered that from lags s.s = its carpels at trameudes through two 
small rhomboidal space urface. The discovery was made nadi ob- 
serving the deportment of a Halictus i in one of the flowers. I peior pee it not only 
gathered the pollen g ; ards th 
tre of the flower. Th en, instructed by i I fl 
found that its nectaries secreted a very dense and white honey. Itis an incontestable 
fact that, in this kind of search honey-bees show r sagacity sy we mae 
The same, however, cannot be said of Diptera, which are in general of obtuse 
gence. And, in fact, all se Sor wers beeen Ane destined an pe preferably visited os 
impollinated by I lidæ, Syrphidæ 
and open nec taries, easily discovered. 
It is singular how hon secreted by the most diferent organs. Thus, in the sin- 
gle pone pen of the Ranuneulacew the honey is secreted, 1, by ~ reddish margins of the 
e Pwonie ; 2, by the petals in Ranun s Mygsurns, Trollius, 
Fx ily sala Nigella, Delphinium, Aconitum, Coptis; 3, by the abortive an- 
thers in Anemone pratensis; 4, by the filament s in some Clematiden; 5, by the carpels 
= ba n gentis Caltha. th example of all 
a ti 
ptis sepals rp 0 and carpels i 
secreting honey. for the advan tage of in 
fThis does not Lae with a SAY, observations, _ Our species of Salvia are visited 
almost exclusively by bees. ey h 
to suck. th Pg i ge gi a of a onions eae eee the 
pollen.upon their backs. Now the honey bees and Bombi collect this pollen carefully, 
with their legs time to time. The is. 
\ 
have frequently i Bombus (I EET B. hortorum or terres- 
) and Xyloc entering one of the three mouths of the flowers of this 
plant, and covering its back with pollen; after visiting two or three flowers it would 
