66 



THE AMERICAN ENTOMOLOGIST. 



falling directly to the earth, would spring 

 up in such dense clumps as to choke each 

 other and endanger the life of all. Every 

 species has to pass through a certain or- 

 deal in the history of its struggle for ex- 

 istence, at which period any, even the 

 smallest, additional obstacle to its progress 

 is sufficient to turn the scale against it and 

 force it to succumb. It is at this time 

 that a wide distribution is of the greatest 

 advantage. With most of the choicest nut 

 and fruit bearing species this is the case, 

 and had no other agency existed for ac- 

 complishing this purpose than those of in- 

 organic nature it is doubtful whether they 

 could have survived. This great service 

 is performed by animals and by birds in 

 a variety of interesting ways. 



The full significance of the many re- 

 markable kinds of fruit can only be under- 

 stood by recognizing this principle. But 

 it must also be remembered that the adapt- 

 ation has been mutual. We cannot assume 

 the various fruits to have first existed and 

 that afterwards the animals and birds came 

 upon the stage and accomplished their 

 distribution. The development of both 

 has gone ow. pari passu from the beginning, 

 and this also harmonizes in a suggestive 

 manner with the known simultaneous geo- 

 logical appearance of these higher forms of 

 vegetable and animal life. Under the law 

 of natural selection, now the fundamental 

 principle of biological dynamics,* berries 

 and fruits have gradually acquired at- 

 tractive dimensions, tastes and colors,f 

 while the true germinal portion, (seeds, 

 drupes, &c.) have been protected from de- 

 struction in various ways, and thus the 

 animal world has been employed to distri- 

 bute the vegetation, for which labor it re- 

 ceives its own subsistence as a remuneration. 

 Not always, however, is compensation thus 

 meted out, for in the many kinds of burs, 

 by whose aid the plant is equally bene- 



* That department of biology which takes account of the 

 changes that have taken place and which are constantly tak- 

 ing place in the form, habits, location and numerical relations 

 of living things. 



t In Medeola Virginica^ the Indian Cucumber-root, I have 

 suspected that the brilliant red color of the upper whorl of 

 leaves which accompanies the ripening of the berries lo'cated 

 at its base, may have been developed through natural selection 

 for the attraction of birds, 



fited, the task of distribution is an invol- 

 untary and unwelcome one to the creature 

 performing it. 



But interesting as these considerations 

 are, and pointedly as they show the inti- 

 mate connection subsisting between the 

 physical life of animals and plants, they 

 are nevertheless trite, in comparison with 

 the astonishing facts which a study of in- 

 sect life in its relation to plants reveals. 



Whether it be true or not, as queried 

 above, that plants may in certain cases de- 

 rive benefit from insects through the agency 

 of galls, it is now certain that they do de- 

 rive such benefit in at least two other en- 

 tirely distinct ways ; viz. — i : by the action 

 of the insects in cross-fertilizing flowers ; 

 and 2 : by the action of plants in entrap- 

 ping insects and appropriating them to 

 their own nourishment. 



Considering the first of these modes, that 

 of cross-fertilization, it is surprising to 

 what extent the evidence already obtained, 

 and that by comparatively few observers, 

 supports the conclusion that for the higher 

 forms of vegetation this reciprocity is one 

 of equality, and that the vegetable king- 

 dom is as absolutely dependent upon the 

 animal as the animal is upon the vegetable. 

 This fact of insect agency in cross-fertiliz- 

 ation which Sprengel, its original observer, 

 appropriately styled " The newly-discov- 

 ered Secret of Nature," has been so far 

 established and extended by recent obser- 

 vation that it has become the key to the 

 greater part of the mysteries of vegetable 

 morphology. In fact it has so enlarged 

 our conceptions of the science that the 

 peculiarities of structure observed in flow- 

 ers are no longer looked upon as positive 

 facts (I use the term positive in the Com- 

 tean sense) but as effects, and we at once 

 proceed to interpret their significance 

 and determine their true cause or raison 

 d' ctre. Just as when the archaeologist dis- 

 covers a singular vessel or implement he 

 refers it to the agency of an intelligent 

 being who must have constructed it, so the 

 modern botanist, when he sees a curious 

 structure in a flower, proceeds by a course 

 of rational deduction to account for it as 



