262 
ARUM MACULATUM AND ITS CROSS-FERTILIZATION. 
By Roserr Minter Curisty anpD Henry CorbDERr. 
(Concluded from p. 240). 
owerful scent or the brightly-coloured spadix attract large 
J eicrais = a small . s of fly,* which, after remaining for 
a moment on the r surface of the spathe, fly down into 
the bulb, pb they » remain fast prisoners, securely shut in by 
the hairs at the mouth, haem a ee slightly downwards 
admit of their Bbtanse but n their exit. The number of 
these flies thus caught is Sy. aie in different flowers, but is 
often remarkably large. We have both repeatedly opened spathes 
ften 
contain 70, 100, 100, 150, and 230 flies. On the Ist of May, 1882, 
we found a large spathe during the See with the spadix cold 
and pollen shed, in which we actually counted no less than 365 
live flies and 12 roe pe or 877 i in all, the vast majority of which 
were of one spec In another spathe we found 45 living and 538 
dead flies. At first ‘: shoupht it seems difficult to say where such 
arge numbers of these usually unnoticed insects can come from; 
but they are so minute that they are tery easily overlooked, and a 
few Gay generally - seen about near large numbers of ‘Arums. 
This species seems to be the Sar one a who habitually gc 
the flowers of A. ma aol tum ; but most spathes contain one or two 
insects of other sorts whic have | most likely got in by aptitent, 
such as sm 
more than one case we have observed dung-flies on the spathes, 
but these are idee a too large to enter. We have also notice 
that slugs (Limaz agrestis) and spiders sometimes enter the bulb of 
e spa es the former probably for shelter and the latter possibly 
for the flies. The heat and smell seldom last more than a few 
wipe believe about six or seven, or perhaps less. Mr. Britten 
dly drawn our attention to a note in the ‘ Phytologist’+ in 
which Th G. B. Wollaston records that his little boy was picking 
* H. Miiller, in his ‘ Fertilisation of ey (see Thompson’s English trans- 
lation, p. 562), states that the only insect he has found within the spathe of 
rum maculatum is the small dipter, Piychodte phalenoides, and that in great 
quantities ; while ate has observed A. italicum to be fertilized by six 
vr 
Psychoda, Limosina, th Drosophila. He thus describes the process of fer- 
tilisation :—“ In the first stage of flowering the stigmas only, which are borne 
by the base of the spadix, are mature; a foul ammoniacal smell attracts the 
e insects dust themselves over and over with it, and finally, be 
the palisade of hairs withers in the fourth period, they pass out, and ente: 
e.”"—A, W. B. 
t ‘ Phytologist,’ 1857, n.s, ii., pp. 45, 46. 
