FLY FLOWERS 129 
flower captures. a number of flies by which it may be fertilized in its second 
condition. Now since, when the flower has opened, the flies do not come to it at 
once, as if responding to an invitation, but are led thither gradually and acci- 
dentally, it follows that this condition must naturally last for a considerable time. 
I have found that it continues six days. During this time chance brings to-day one 
fly to the flower, to-morrow two or three, and each of them, deceived by appear- 
ances, creeps in. In this way quite a considerable company of these little animals 
are at last gathered together, and such an unexpected meeting in so narrow a 
Fic. 42. <Artstolochta Clematztis, L., a Pitfall Flower (after Sachs). (1) Flower in the first (female) 
condition: the perianth tube is internally beset with oblique downwardly directed hairs, the stigma is 
developed, the anthers (a2) are closed. (2) Flower at the end of the second (male) condition: the hairs of 
the perianth tube are almost dried up, the margins of the shrivelled stigma are curved upwards, the anthers 
have dehisced. 
chamber, such an undeserved incarceration in a prison so well secured, may indeed: 
appear sufficiently strange to them. But none of them has pollen on its body, for 
the anthers have not yet opened. To this succeeds the second condition, in which 
the flower has ripe pollen, a well-developed stigma, and a sufficiency of flies to bring 
the former to the latter. Frequently, indeed, this may not be brought about, for 
here also everything is left to chance, but it must often be easily accomplished.’ 
‘The flies, naturally enough, seeing that they have been so long walled in and 
have had nothing to eat, become impatient, and indignantly run about in the trap. 
Moreover, when they are in such a mood, conflicts cannot easily be avoided, and in 
these small prisons, into which the human eye cannot look, may at times go on in 
a tolerably warlike manner. In some such way the insects must come upon the 
anthers among other things, removing their pollen, carrying it about everywhere, and 
depositing it on the stigma, among other places. - This condition cannot be of long 
duration. And it therefore happens that one seldom comes upon an erect flower 
exactly presenting it, and most of them when cut open prove to be still in the first 
condition. In this second condition it is often found that the flies, which are black, 
have something white on their backs. This is the pollen dust. As soon as Nature has 
attained her end, the flower passes into the third condition. It reverses its position, 
DAVIS K 
