343 
along the spadix. thus detaching the inner coils of the spathe from 
their grasp upon the anther cells. A copious discharge of mucus from 
the walls of the spathe causes the released pollen to stream down into 
the cavity below, converting the limpid liquid into a turbid, soup-like 
mixture. Every portion of the interior is soon bedaubed with a farina- 
ceous paste, upon which the swarming larvae live and feed riotously. 
They finally pupate and transform to perfect beetles. In the meantime 
the diseased spor in the spathe completes its growth and drops away, 
leaving a yawning orifice, through which other saprophagous insects 
gain an entrance and add their increase to the swarming population of 
the flower. Prominent among these is a fly maggot, similar to those 
which infest fungi. This maggot feeds upon the ripening parenchyma 
of the tloral envelope and destroys it. The liquid within the cavity 
becomes putrid, and finally escapes through the breaking down of the 
containing walls. 
The brood of Macrostola beetles, by this demolition of their domicile, 
are driven forth to mate and betake themselves to neighboring flow- 
ers, where they repeat the process just described. They bear with 
them in the pollen paste with which their bodies are plentifully 
bedaubed, the material necessary for the fructification of the new 
inflorescences into which they enter. 
The part played by the rot-fungus is an important one, equally 
advantageous to the beetles and to the plant. It aids the former by 
first softening the tissues of the spathe, thus allowing the beetles to 
advance in their passage into the flower-case, and afterwards harden- 
ing and for the time being effectually closing the entrance against 
other intruders. After the Macrostolas. in undisturbed possession of 
the flower-case, have accomplished the fertilization of the stigmas and 
released the pollen, the fungus in maturing breaks the seal of the 
plant and admits destructive insects. The aroid thus secures the 
expulsion of its pollenizers as well as the proper ripening and dissemi- 
nating of its seed. 
Observations upon the fertilization of aroids are not often met with 
in botanical literature. The flowers of the more common northern 
species have been studied by various authors, but the tropical forms 
have been seldom examined in their native habitats, and most of the 
observations upon their methods of fertilization have been made in 
European greenhouses. 
The flower-cases of many species exhale powerful, often foul and 
putrescent, odors, which attract scavenger insects of various kinds, and 
slugs, also, being particularly abundant in greenhouses, have often been 
observed creeping about the flowers. Not a few of the records made 
under these unnatural conditions add but little to our knowledge of 
the manner in which the fertilization of these plants is accomplished 
in the tropical forests where they are at home. 
The treatise of A. Bugler upon the arrangement of the sexual organs 
