342 
As tbe result of the examination of numerous flower-cases, the fungus- 
spot was found to increase in area until it reached the size of a shilling 
piece. Its growth then ceased. In the meantime the tissues affected 
by the fungus shrink and finally split, leaving an opening into the 
cavity of the spathe through which saprophagous insects can enter 
at will. 
In examining flowers not yet attacked by the fungus, or in which its 
presence is barely indicated by a slight discoloration, the author of the 
contrivance is frequently disclosed. This is no other than a sap-beetle 
of the family Mtidulidse, a pair of which, male and female, are invari- 
ably found together, forcing their thin bodies under the overlapping 
fold of the spathe. Mr. E. A. Schwarz has identified this beetle with 
Macrostola lutea Murray, described from Cumana, Venezuela. 
Fig. 33, c gives an outline of the beetle, with its antenna and front 
leg more enlarged. The hair line at the side of tlie figure shows the 
natural size. 
The Macrostolas evidently consume some days in gaining an entrance 
into the flower-case. In this laborious effort they are materially 
assisted, first by the plant, which has accommodatingly reduced the 
distance to be traversed by the beetle by means of the sinus in the edge 
of the spathe, without, however, in the least degree breaking the seal 
of the flower-case. The instinct of the beetle in selecting this weakest 
point for its attack appears to be unerring. Secondly, I believe that 
the aid afforded by the rot fungus, Avhich promptly attacks the surface 
gnawed by the beetles in their effort to cut a passage onward, is most 
material in causing the tissues of the thick and leathery spathe to 
soften and perhaps to warp slightly in shrinking Thus the beetles are 
enabled to accomplish that which without this assistance would be 
impossible to their feeble powers. At any rate, the passage of the pair 
of insects is made without, for the time being, breaking the closely 
guarded seal of the plant, and they enter into undisturbed possession 
of their new home. The point of entrance lies just above the surface 
of the liquid in the cavity. Once inside, the beetles make their way to 
the spadix, and force a passage upward along its polleniferous portion. 
The female, as she proceeds, deposits eggs, which soon produce a 
numerous colony of larvse. By the time their progeny are half grown, 
the parent beetles, having fulfilled the measure of their existence, 
perish. Their dead bodies will invariably be found together at the upper 
end of the spadix, firmly wedged beneath the fold of the spathe, and 
incased in a thick paste of pollen grains agglutinated by the mucilage 
of the plant. # 
The brood of larva? live and complete their growth within the flower- 
case, feeding upon the pollen, in search of which they burrow and mine 
* A similar life-long attachment and association of a single pair of adult beetles 
has been noticed by me in the case of Epurcea monogama Crotch, another member of 
the family Nitidulidse. Compare, " Inhabitants of a Fungus." (Can. Ent., vol. 
xxiv, 1892, pp. 250 If.) 
