28 



Riley Presidential A ddress. 



tion is a result of a difference in the kind of food or amount of 

 food supplied by the nurses; so that practically the constitution 

 of the formicary is regulated by the colony itself. The helpless 

 larvae and pupae are moved from place to place, and most ten 

 derly cared for by the nurses, which understand the requisite con 

 ditions of warmth, fresh air, protection against cold, rain, and 

 other injurious influences, and Avhich feed their young charges 

 with a liquid discharged from the mouth, very much as in the 

 case of the bee. 



While the mandibles are used for tearing all sorts of sub 

 stances, it is the juices of these which are lapped up by the ton 

 gue, and which can be regurgitated from a fore-stomach or 

 pouch, in order to feed the young and tlie queens. These young 

 are, also, arranged by the workers in groups of different sizes and 

 ages, with a view to regulate the amount of food necessary for 

 each stage. The larval life varies very much, so far as observa 

 tions have been made, as its duration may extend from six or 

 seven weeks to several months, according to the species. Some 

 species even hibernate in the larva state. I have already indi- 



FIG. 7. HONEY ANTS : Myrmecocistus mexicanus ; a, side view ; b, from above en 

 larged, the outlines showing natural size, (after Lubbock.) 



cated the differences in habit as to the formation of a cocoon or 

 pupation without a cocoon, in the different families of the group; 

 but a difference is noticeable in this respect, even in the same 

 formicary, as first observed by Latreille. Those which pupate 

 in cocoons are often unable to extricate themselves when mature, 

 and are then tenderly assisted by the workers, who also aid in 

 the unfolding of the wings, and cleansing of the newly-developed 

 ant. (Fig. 6, shows a typical larva, nymph and cocoon). 



The individuals of the formicary are therefore composed (1) 



