NOTE ON THE COLORATION OF INSECTS. 3 



and arrived at results so interesting that I have published them in a 

 work entitled Obsen-atiuns on t/ic Coloration of Insects, which appeared 

 in 1897. 



My conclusion was that observed facts do not allow us to admit that 

 this phenomenon can bo attributed exclusively to ' ' Darwinian selec- 

 tion," but that, on the contrary, primitive coloration is due to influences 

 which are entirely independent of the Avelfare of the animal, and some- 

 times even contrary to its needs. The adaptation to the demands of 

 the creature is a secondary action and this only is brought about in 

 accordance with the laws of selection. 



Naturalists, misled by Darwin's ingenious theory, shook their heads, 

 and it was especially in England that I met the most serious opposi- 

 tion. My opponents did not deny the facts referred to, but raised the 

 objection that we know too little of the various phases of the phylo- 

 genetic development of the species to be in a position to pronounce a 

 verdict upon the utility of the qualities which we observe. 



I thoroughly agree that we are far from appreciating the influence 

 of external causes upon the modification of the species, but on a minute 

 examination of colour, it is impossible to admit that it is the result of 

 a slow and gradual modification such as selection demands. 



Of the numerous examples referred to in my work, I choose one to 

 illustrate my point. Masta.c semicacca, a little grasshopper of the family 

 Acridiodea, and a native of the Upper Amazons, is of a dark olive colour. 

 The uniformity of this colour is broken up by a lateral yellow band of 

 equal breadth, Avhich runs the entire .length of the insect. It begins at 

 the head, crosses the lateral lobes of the pronotum and continues along 

 the abdomen, regardless of the position and arrangement of the different 

 organs. This band has caught the lower half of the eyes, and I 

 think that the visual powers of the insect are thereby impaired. An 

 objection could" be raised that at a certain epoch the diminution of this 

 faculty was advantageous to the insect, and there are several cases of a 

 modification of the visual power, insects which live in caves, for 

 example ; but in these cases it can be shown that this result is obtained 

 by a gradual obliteration of the eyes. It is the natural method 

 responding to the action of selection. The application of a bandage is 

 usual in the operating chamber of an oculist, but does not occur in 

 biological genesis. 



May I be allowed to add a point that is very liable to escape observa- 

 tion, a minute question of coloration in the front leg of Hierodula 

 notata, a Mantis from Borneo? The front legs are not adapted for 

 walking, but are used by these voracious animals as weapons for seizing 

 their prey. When in a state of repose there can be seen in the middle 

 of the under surface of the femur a black round spot. When the foot 

 is extended this spot is broken. One part of the black colouring is on 

 the femur, the other on the spines of the tibia, which, in repose, is 

 closed against the femur. The round black spot is formed, therefore, 

 by a combination of two organs in a certain fixed position. If this 

 spot is produced by natural selection, and if it is developed by an action 

 which is part and parcel of the animal, it follows that organs, entirely 

 distinct in their nature, are made use of to produce a black spot. 

 Further, if this spot had been misplaced by a single millimetre, it 

 would have fallen entirely upon the surface of the femur and its pro- 

 duction would have been far more simple. According to my theory 

 that coloration is a property emanating from an external power that 



