474 THE POPULAR SCIENCE MONTHLY. 



insects which produced a given result with least labor to themselves, 

 an established instinct. Further questions may be now asked : Why is 

 it that any other insects besides neuters have been produced ? As they 

 can not propagate their kind, how have they become gifted with the 

 instincts to take care of and to feed the young, provide food for the 

 colony, build nests, etc. ? 



To the first question a sufficient reply is, that, if nothing but neuters 

 were produced, there would be no insects. The other questions may 

 be answered by an amplification of a statement already made. Neu- 

 ters, as a rule, are sterile females ; the exceptions to this will be con- 

 sidered further on ; they inherit the instinct of females and perform 

 their duties with the one exception of ovulation. To give a few de- 

 tails : Originally there were no neuters ; and as females were numerous, 

 each female would lay comparatively few eggs. How the neuters 

 arose we have already seen ; at first they were few, gradually increas- 

 ing until they equaled and finally outnumbered the females. At the 

 same time the labors of the female became more restricted ; as they 

 decreased in number they must, in order to keep up the colony, lay 

 more eggs : as a result, the extra time devoted to ovulation was so 

 much time taken from cell-building, nursing, etc. Applying this 

 theory to facts, we can see why with the increase of neuters the duties 

 of the queen-bee have grown less and less until they consist of nothing 

 but ovulation. The queen-bee is a queen only in name, receiving just 

 such extra care that her time may be entirely devoted to propagating 

 the species. At such time when each hive only contained one reigning 

 queen, this female had to assume the reproductive functions of her 

 twenty thousand sterile sisters, and it is not strange that she has no 

 time to build or to feed the young. Under no other conditions could 

 she lay her two thousand to three thousand eggs a day. The case of 

 the termites or so-called white ants is more striking, the female laying 

 eighty thousand eggs in the course of a day, or very nearly one egg a 

 second continuously. What other duties can this huge animated egg- 

 sac perform ? 



With existing social insects, as a rule, the male does little or no 

 work but that of fertilizing the females, but before the appearance of 

 neuters we may suppose he had other duties. With many beetles the 

 male performs a large share of the labor ; the male of the burying 

 beetle, for example, excavating the grave in which its prey is buried 

 and in which the female deposits her eggs. With many insects the 

 male defends the nest or burrow from the attacks of invaders, of which 

 take an example quoted by Mr. Darwin in his " Descent of Man " : 

 " The two sexes of Lethrus cephalotes (one of the Lamellicorns) inhab- 

 it the same burrow. If during the breeding season a strange male at- 

 tempts to enter the burrow, he is attacked ; the female does not remain 

 passive, but closes the mouth of the burrow and encourages her mate 

 by continually pushing him from behind." That males are not always 



