119 



FLOWERS AND THEIR UNBIDDEN GUESTS. 



In the September number we consi.I- 

 ered flowers and their invited guests, tliat 

 is the insects useful in carrying pollen. 

 The very things which attract useful in- 

 sects to flowers are attractive also to use- 

 less insects. For example, nectar in a 

 flower seems just as desirable to an ant 

 as to a butterfly, but the ant is a creeping 

 insect and would be likely to lose the 

 pollen in passing from one plant to an- 

 other. If useless insects found free ac- 

 cess to flowers and carried ofif their food 

 supplies, the useful insects would soon 

 stop visiting them. It is of great advan- 

 tage to flowers, therefore, to have some 

 means of warding ofif the creeping in- 

 sects. It must not be understood that ?11 

 plants are equally successful in this mat- 

 ter, or that any plant is always successful, 

 but there are certain things which seem 

 to hinder or discourage the approach of 

 creeping insects to flowers. 



Perhaps ants may be taken as the best 

 illustration of the insects whose visits are 

 discouraged by flowers. They are very 

 much attracted to the food supplies in the 

 flower, especially the nectar, and are 

 among the most intelligent of insects, 

 often overcoming the most serious ob- 

 stacles. They will be considered in this 

 paper, therefore, as the insects which are 

 seeking the nectar and pollen of flowers 

 without invitation. A charming little 

 book upon this subject has been written 

 by Kerner, and translated into English, 

 under the title which appears at the head 

 of this paper. It is in this book that the 

 chief obstacles to such unwelcome guests 

 as ants are clearly stated. 



Hairs. — One of the most common ob- 

 stacles to ants is a barrier of hair. For 

 some reason, ants dislike to cross such a 

 barrier. Travellers in tropical countries, 

 where ants abound, tell us that a hair rope 

 laid around a tent is a very effective bar- 

 rier against the invasion of armies of ants. 

 Hair is very commonly foimd upon 



plants, and it may be noticed that it is apt 

 to increase in amount and prominence 

 towards or within the flower cluster. Some- 

 times the flowers themselves are hairy out- 

 side,andinthecaseof the trailing arbutus, 

 whose flowers close to the ground are in 

 special danger from creeping insects, the 

 flowers are filled with a fluffy mass of 

 hairs. In our illustrations, the wild co- 

 lumbine, the Oswego tea, the sunflower, 

 and the ox-eye daisy are all hairy plants, 

 and difificult for ants to climb. In the 

 September number are illustrations of the 

 mallow, the lady's slipper, and the New 

 England aster, all of which are hairy and 

 discouraging to ants. 



An interesting fact in connection with 

 the wild columbine may be noted. The 

 nectar is deposited in the knob-like bot- 

 tom of the long tubular spurs, and the en- 

 trance is so carefully guarded that only 

 a long and slender proboscis, like that of 

 a moth or a butterfly can reach the nectar. 

 The bumblebees, however, have learned 

 this fact, and bite through the tips of the 

 spurs and steal the nectar. As a conse- 

 quence, the wild columbine is said to be 

 little visited by the proboscis-bearing in- 

 sects, and its pollination is seriously in- 

 terfered with. 



Sticky excretions. — Some plants have 

 the power of excreting upon their surface 

 a sticky substance like mucilage. This 

 mucilage may be produced by hairs, 

 which are then called "glandular hairs," 

 or it may appear directly on the surface 

 of the plant. When ants or other insects 

 try to cross such a barrier they are not 

 merely stopped but caught. Upon 

 "glandular" plants it is very common to 

 see small insects stuck fast, and it is more 

 than probable that the nourishing ma- 

 terial of their bodies is digested and ab- 

 sorbed by the plant. In this way the plant 

 not merely stops the insect, but catches 

 and devours it. 



A very common illustration of such a 



