PACKAun] THE SOCIAL LIFE OF INSECTS. 349 



and hit on a plan of building which proved advantageous to 

 the species, when Nature stamped her approval of the reform 

 by preserving the species in the condition we now behold. 



When the workers appear they aid in bringing home sup- 

 plies of pollen and hone}', but do not build, and in fact the 

 humble bee is not much of an architect. 



In the stingless bees (Melipona and Trigona) of the trop- 

 ics, however, we have a high degree of architectural skill 

 shown in the construction of their cells. The domestic 

 Melipona of Mexico constructs combs of hexagonal cells 

 smaller though like those of the honey bee, but they also 

 have large irregular roundish cells an inch in diameter, which 

 serve as honey pots. According to Fritz Mijller, who has 

 observed these bees in southern Brazil, the wax is secreted 

 on the upper side of the abdomen, instead of the under, as 

 in the hive bee. The wax is usually dark-colored, but sus- 

 ceptible of bleaching. He also states that while the larvae 

 of the hone}^ bee are fed l>y the laborers at first with semi- 

 digested food, and afterwards with a mixture of pollen and 

 honey, and while the cells are closed only where the larva? 

 ai'C full-grown, "the Meli[)on;e and Trigonre, on the con- 

 trary, fill the cells with semi-digested food before the eggs 

 are laid, and they shut the cells immediately after the queen 

 has dropped an egg on the food. With hive-bees the royal 

 cells, in which the future queens have to be raised, differ in 

 their direction from the other cells ; this is not the case with 

 Melipona and Trigona, where all the cells are vertical, Avith 

 their orifices turned upward, forming horizontal (or rarely 

 spirally ascending) combs." 



The colonics of these bees are exceedingly populous, the 

 workers being numbered by the thousands. Smith says that 

 "Mr. Stretch, who lived at Panama, described a hive that he 

 saw, occupying the interior of a decaying tree, that meas- 

 ured six feet in length, and the multitude of bees he com- 

 pared to a black cloud." This colony belonged to a species 



29 



