66 PREDATORY PLANTS. [CHAP. 
in Arum (p. 41, avte). The Virginian Swallowwort 
(Asclepias syriacus), and the Oleander (Verium olean- 
der), are also included among those plants which 
entrap insects by means of their flowers. 
In a paper recently read before the Entomological 
Society, Mr. J. M. Slater stated that certain gay- 
coloured flowers are avoided by bees, or, if visited, 
have an injurious and even fatal effect upon the 
insects. Among these are the dahlia, passion-flower, 
crown imperial, and especially the oleander. That 
the flowers of the dahlia have a narcotic effect was 
first pointed out by the Rev. L. Jenyns, who men- 
tions that bees which visit these flowers are soon 
seized with a sort of torpor, and often die unless 
speedily removed. Mr. Jenyns also quotes a writer 
in the “ Gardeners’ Chronicle,’ who pronounces the 
cultivation of the dahlia incompatible with the suc- 
cess of the bee-keeper. The passion-flower also 
stultifies bees, and bees of all kinds avoid the crown 
imperial and the oleander, for the honey of the latter 
is fatal to flies. Mr. Slater did not remember ever 
having seen a butterfly or moth settling on the 
flowers of this shrub in Hungary or Dalmatia; and 
he thinks it important that observers should ascertain 
whether the above-mentioned phenomena be true, 
_and whether any insects in such cases undertake 
the functions [of fertilisation] generally exercised by 
bees, and whether flowers have a similarly noxious 
or deadly action upon insects.—Sczence Gossip, 1879, 
p. 164. 
In addition to these plants above named, there is 
a group of others that is really insectivorous, The 
