SOCIAL INSECTS , If) 



may often be seen to push the head-end well 

 out of the burrow for purposes of feeding ; at 

 other times the tail - end is pushed out and 

 waved to and fro in the water, as a help to 

 respiration." This may be compared with 

 Atheston on Tubifex: "It forms flexible tubes 

 open at both ends, of particles of soil cemented 

 by mucus. When contracted, the worm lies 

 wholly within the tube. When active, the 

 posterior end (third or half of the body) pro- 

 jects into the water, waving about in a rapid, 

 undulatory manner, while from the other end of 

 the tube is protruded the anterior end of the 

 worm which is thrust about through the mud 

 in search of food." Limnodrilus, as observed 

 by me in Ceylon, forms dense aggregates of 

 individuals surrounded by mud, but does not 

 form definite tubes which can be isolated from 

 the clumps. 



No example of bionomical convergence is 

 more remarkable than that which is presented 

 by the social insects, ants, bees, wasps, and 

 termites. The termites so much resemble ants 

 in their mode of life and social organisation 

 that they are commonly known in the tropics 

 as white ants, though they are not ants and 

 are not always white. Not only have they 

 no direct genetic relationship with the true 

 ants (Formicidse, order Hymenoptera), but the 

 latter are among their most formidable enemies. 



