ANTS AND MYRMECOPHILS 405 



Wheeler (22) outlines the question of the spinning of cocoons 

 by ant larvae and calls attention to the fact that in the families 

 Dorylinae, Myrmicinae, and Dolichoderinae the larvae never 

 spin cocoons before pupation. He further points out that he 

 has already published evidence as shown by the ants found in 

 Baltic amber that there must have been forms with naked pupae 

 at least two million years ago. This would seem to settle con- 

 clusively, in the negative, any question as to the recent origin 

 of the non-spinning habits of 'certain ant larvae. The fact that 

 the mature ant larvae cannot spin its cocoon without first being 

 buried in a small mass of rubbish or in the earth makes it possible 

 that the origin of the non-spinning habit is the result of a dropping 

 out of this burying behavior upon the part of the adults rather 

 than to a loss of spinning ability upon the part of the larvae. 

 Wheeler cites a considerable list of ant species in which the 

 larvae are great spinners but in which the spinning act'vities 

 go toward the making of a nest for the entire colony and the 

 larvae never spins a cocoon for itself. As an example of this 

 altruistic behavior the author records some observations which 

 he made in Australia on Oecophylla virescens. He spent some 

 time observing under favorable conditions the nest making 

 activities of this species which makes its nest by weaving to- 

 gether the leaves on a branch of a tree. The weaving is done 

 by the adults but the larvae furnish the silk and are carried about 

 in the mandibles of the adult and used as a shuttle until their 

 supply of silk is exhausted. He noted also that young larvae 

 were most commonly used. Most of the work is done from the 

 inside of the nest and is therefore not easily observed. Wheeler, 

 however, fortunately saw part of the work being done on the 

 outside of the nest. 



In the latter part of the paper Wheeler discusses briefly colora- 

 tion of ants in general. 1. Some ants are white or light colored. 

 These forms usually live in the dark. 2. A number of species 

 exhibit a progressive development from red, brown or black to 

 the interference colors. This is noticeable in ants living in hot 

 dry sunny climates. Many of the Australian ants show inter- 

 ference colors. 3. There are large eyed tropical ants that are 

 black and yellow with red spots and bands. Their general 

 appearance is made more striking by the presence of a white or 



