670 IOWA DEPARTMENT OF AGRICULTURE. 



species, apparently without understanding tl^e object at which it may be 

 supposed to aim or without deliberating as to the best methods to employ. 

 There are many actions of the bee which are carried out by newly hatched 

 bees and for which we can see no cause. The difficulty here is that 

 whenever an observer comes across an action which he cannot understand, 

 and for which he can find no method of formation, he throws it into the 

 general pile of "instincts" without further effort to find a cause. Is it 

 not evident that what we so often call instincts are but actions which 

 we do not understand? I believe, and I am not alone in my belief, that 

 every instinct has a physical cause in the structure of the animal or its 

 environment, and unless we do our utmost to arrive at the ultimate 

 cause of these actions we have not finished our problem. There is a 

 tendency for all men to think that when they have a name for a thing 

 and can use the word fluently that they understand all the details of 

 the question, but we must constantly avoid this. As an example of this, 

 let us take the duties of the bees at different ages. Briefly, they work 

 as follows: For the first day or two the young bees do not work, on 

 account of their weak condition, but they soon take up the duties inside 

 the hive, such as wax-building, nursing the developing larvae, cleaning the 

 hive, etc. Later, generally when about sixteen to nineteen days old, they 

 begin to fly from the hive and ordinarily never do any of the inside 

 work of the hive which they did before. Of course, it must be under- 

 stood that varying conditions may change their actions, but this is what 

 normally happens. Young bees do, of course, fly from the hive in what 

 is called their exercise flight on warm afternoons, but they do not go 

 so far from the hive but that they can be guided back by their sense of 

 smell. "Why do they go through this cycle? We can, of course, say that 

 instinct impels them to do all these things, but how much more do we 

 know about it when we have given a name to the impulse unless we 

 look farther? 



I have not investigated this problem very much, and do not wish it 

 understood that I think that I have arrived at the ultimate and complete 

 cause of this cycle of action, but certain facts seem to me to indicate 

 that there is an organic cause back of all this. The large compound 

 eyes, as well as the ocelli of the young bees, are covered with fine hairs, 

 each one of which' is much longer than a single unit of the eye. These 

 hairs are not sensory, as Cheshire claims, since they are in no way con- 

 nected with the nervous system. I can also see no reason why they 

 should be considered as protective, since the chitinous lens of the eye 

 is very dense and seemingly needs no protection of this kind. These 

 hairs come off gradually and by the time the bee is ready to fly they are 

 nearly all gone. 1 do not wish to make the mistake of failing to distin- 

 guish between accompanying and casual factors, but I am inclined to the 

 belief that these hairs on the young bees so obscure their vision that they 

 do not fly from the hive to forage because they cannot see clearly enough to 

 do so. As we know, young bees do fly for exercise, but, as before men- 

 tioned, only so far that they might be guided back by scent. 



Whether my view is correct or most erroneous, all must admit that 

 it is no worse than the position of the man who says that it is all due to 



