15S 



THE POPULAR SCIENCE MONTHLY.— SUPPLEMENT. 



other class of carrion-feeding insects which have 

 likes and dislikes more in unison with the vul- 

 tures, the turkey-buzzards, and the jackals. Since 

 it is possible for life to be sustained upon decay- 

 ing animal matter, it must result that some small 

 class possessing the unusual taste for carrion will 

 be able to gain an easy living upon this undis- 

 puted prey. Hence the growth of such uncanny 

 creatures as flies, condors, and sopilotes. Ac- 

 cordingly, we find certain flowers adapting them- 

 selves to these abnormal tastes, and acquiring the 

 appearance and smell of decaying meat. The Su- 

 matran Jfafflcsia, and the South African Hi/dnora, 

 are large and lurid blossoms, which thus deceit- 

 fully induce the carrion-flies to visit them for the 

 purpose of laying their eggs, and are accordingly 

 fertilized by means of an organized deception. 

 To naturally frugivorous man the scent and the 

 appearance are alike disgusting. 



Lastly, we arrive at the device of color, the 

 most important of all from an aesthetic stand- 

 point. We have seen already how reds, yellows, 

 and purples, came to be developed in the neigh- 

 borhood of the floral reproductive organs, but we 

 have yet to inquire why they should prove at- 

 tractive and pleasurable to the eyes of insects. 

 In order to do so properly, we must glance a lit- 

 tle at the nature of pleasure generally. 



Without entering into any ultimate physiolog- 

 ical question, it will suffice for our present pur- 

 pose to point out that pleasure results from the 

 normal stimulation of any fully-nurtured and un- 

 derworked nervous structure. For instance, in 

 a state of health, our limbs, when properly fed 

 and not previously fatigued, derive pleasure from 

 the mere act of exercise. So with each of our 

 senses; any particular stimulation is pleasant if 

 it has been sufficiently intermitted, and is not ex- 

 cessive in amount. Now, if we apply this sim- 

 ple principle to the case of sight, we shall see 

 that, so soon as the eyes of insects have been 

 differentiated enough to discriminate the pinkish 

 or ruddy tips of boughs from the green leaves 

 about them, the special nerves involved in this 

 process will receive pleasure from their due stim- 

 ulation. The more intermittent each such stimu- 

 lation may be, the more pleasurable will be the 

 resulting sensation. So we can see how, as the 

 petals of flowers grew gradually more and more 

 distinguishable in color from the green leaves 

 about them, and as the eyes of primordial bees 

 or butterflies grew gradually to distinguish them 

 better and better, an ever-increasing pleasure 

 would grow gradually up by their side, and be- 

 come stronger and stronger as the nerves in- 



creased by practice in calibre and strength. And 

 so, too, we can understand how at last we reach 

 the pure and brilliant coloring of the gladiolus, 

 the laburnum, the hyacinth, the peony, and the 

 tulip ; and how the insect eye is drawn on by the 

 pleasure hence arising to the nectary of the flow- 

 er, and to the pollen or the stigma from which 

 the future seed is to take its rise. 



Here, too, in like manner, we may observe 

 the practical identity of taste in the flower-feed- 

 ing insects and the fruit-eating vertebrates — in- 

 cluding the human species, who, as we have al- 

 ready noticed, derive their likes and dislikes from 

 their frugivorous ancestors. For, just as the 

 sweetness of fruits answers to the sweetness of 

 honey, and just as the scent of fruits answers to 

 the scent of flowers, so the colors of fruits are 

 identical in origin and nature with the colors of 

 flowers. It would seem as though in every case 

 Nature found a single mode of modifying the 

 nervous substance was amply sufficient (because 

 simplest and easiest) alike for insect and reptile, 

 for bird, and ape, and human being. 



As for the particular color of each particular 

 species, little is known as yet of its determining 

 causes. In a few cases we can plausibly account 

 for the special hue selected ; thus the plants 

 which depend for fertilization upon carrion-in- 

 sects naturally imitate the lurid-red appearance, 

 as well as the noisome smell, of putrid meat ; 

 while the night-flowering blossoms are apt to be 

 white or bright yellow, as those colors best re- 

 flect the scanty light of evening or the scattered 

 rays of the moon. But in the majority of in- 

 stances we can scarcely hazard a conjecture as to 

 the reasons which have influenced insects in their 

 unconscious selection. It must suffice to point 

 out that in many cases the spots, lines, and bars, 

 on the flower seem to act as guides for the insect 

 in discovering the exact locality of the honey- 

 store, while in others they are placed for some 

 purpose of mimicry which is directly or indirect- 

 ly useful to the species. With this brief indica- 

 tion of a great field for future inquiry, we may 

 pass on to some other interesting aspects of the 

 color-sense as applied to flowers. 1 



As the object of the colored whorls is merely 

 to attract the attention of insects, it docs not 

 matter, of course, which particular whorl is sup- 

 plied with pigment in each instance. It is only 



1 Those who wish to find out how much is already 

 known on this curious point of special adaptations 

 may turn to Mr. Darwin's work on " Orchids," or to 

 Sir John Lubbock's on " British Wild-flowers in their 

 Relation to Insects." 



