INSECT COMMUNITIES 283 



with which it lives. Apparently the intruders possess 

 suave manners, for the alarm and resentment aroused 

 by their entry soon give place to harmony. Not only are 

 the Psithyrm grubs fed and tended by the Bombus 

 workers, but the adult insects of both sexes consume 

 much nectar from the common store, with the result 

 that the increase of the community is seriously hampered. 

 A nest infested by Psithyrus was found, in September, to 

 contain only one Bombus queen and fifteen workers ; yet 

 in normal circumstances the same species of humble-bee 

 would have increased during the summer to at least 200. 

 The ultimate success of a humble-bee community is in 

 ratio to the number of young queens which are reared at 

 the close of the season. These alone survive the winter ; 

 and when their nuptials are accomplished, the prosperity 

 of the nest declines, while its whole population of drones 

 and workers perishes when the first severe frosts 

 set in. 



The tropical Meliponas or "mosquito bees" (so called 

 on account of their diminutive size) appear to form a con- 

 necting link between humble-bees and hive-bees, though 

 little is yet known of their life-histories and habits. They 

 nest in hollow trees, form definite combs of waxen cells, 

 and often amass rich stores of honey. A colony comprises 

 the usual castes ; but the drones are said to take part in 

 the labours of the community, while there is reason for 

 thinking that more than one queen may be tolerated in 

 each nest. It is also believed that a complete ration of 

 pollen and honey is placed with the egg in the cell, the 

 latter being then sealed down by the workers — a primitive 

 method of feeding reminiscent of the solitary bees. The 

 Meliponas are either unable or unwilling to sting ; but 

 they fight desperately with their mandibles, and have 

 highly developed instincts. Many of them are clever 



