410 Macfarlane .- — Observations on Pitcher ed 
hastens decomposition, according to Drude 1 is probably acid 
and causes a true digestive change. In 5. crispata , a probable 
hybrid between S.Jiava and vS. rubra , a very large quantity of 
sweet juice is secreted by glands on the top of the conducting 
surface, beside that secreted by the lid-glands. This form has 
proved, in the houses of the Edinburgh Botanic Garden, the 
most efficient fly-catcher ; but not only so, some constituent of 
the secretion is of a decidedly acid nature, and at once causes 
litmus-paper to become red. These glands are continued 
down the ventral part of the conducting-area to fully half 
its depth, and if we take into consideration the occurrence 
of them so far down, as also their excretion of a sweet and 
acid juice, the hypothesis which I have advanced above does 
not seem unwarranted. The lower glands of the tube secrete 
even in young unopened pitchers, a juice which Mellichamp 
well describes as being mucilaginous and astringent. If, then, 
the lower glands in simpler types of the genus once secreted 
a sweet juice, its place has been entirely usurped by the more 
useful insect-wetting, and perhaps digestive, juice. 
S. Jlava. This, the strongest growing species of the genus, 
is richly provided with alluring glands disposed in an 
interesting manner. Since the strong vascular bundles which 
traverse longitudinally the external pitcher-surface form 
projecting ribs, lines of glands occur along these as well as 
on the dorsal wing ; many baited pathways therefore, sup- 
plemented by glands scattered less abundantly over the 
surface, allure insects upwards. Fresh healthy pitchers 
examined about the beginning of June show transparent 
droplets of honey exuding from them, and the secretion may 
be continued into autumn, or cease to a large degree during 
summer and be renewed in September. Alluring-glands 
closely stud the external margin of the pitcher-orifice. But 
insects often pass up the ventral rib on the outer lid-surface, 
and accordingly its margin has a perfect cincture of glands 
from which a sweet secretion pours forth copiously. I am 
surprised that this honey-cincture does not seem to have 
1 Op. cit. p. 136. 
