320 WHEELER— ANT LARV^. 



domens dotted with the small brown scars of the wounds thus in- 

 flicted by their progeny. Here the feeding behavior of the mother 

 and offspring is the reverse of that in incipient ant colonies, since 

 the queens are fed with regurgitated food by the workers and feed 

 the latter with exudates, but this is, in all probability, also the case 

 in established ant colonies when the workers have matured and the 

 queen no longer feeds the brood. 



The facts collated in the foregoing paragraphs relate to the exu- 

 date organs, but we had previously seen that the salivary glands of 

 larval ants probably subserve a similar function in the life ,of the 

 colony in addition to digesting proteid foods extraintestinally and 

 producing silk at the time of pupation. The question arises as to 

 whether there is any evidence that in other groups of social insects 

 the salivary glands of the larva produce substances which are con- 

 sumed by the worker nurses. Fortunately there are some very per- 

 tinent observations at hand in the French literature which is so rich 

 in splendidly original works on the habits and taxonomy of insects. 

 The observations to which I refer relate to the social wasps. Du 

 Buysson (1903) observed that the larvje of Vcspa "secrete from 

 the mouth an abundant liquid. When they are touched the liquid 

 is seen to trickle out. The queen, the workers and the males are 

 very eager for this secretion. They know how to excite the off- 

 spring in such a way as to make them furnish the beverage." And 

 Janet (1903) was able to prove that the secretion is a product of 

 the salivary, or spinning glands and that it flows from an opening at 

 the base of the labium. " This product," he says, " is often imbibed 

 by the imagines, especially by the just emerged workers and by the 

 males, which in order to obtain it, gently bite the head of the larva." 



The most illuminating study of this matter, however, is found 

 in a fine paper by Roubaud on the wasps of Africa (1916). His 

 account of the primitive wasps of the genus Bclonogaster presents a 

 striking picture of one of the earliest stages in the social life of 

 wasps, as will be seen from the following quotation : 



In the species of Bclonogaster as well as in those of the genera Icaria 

 and Polistes we have been able to observe this proceeding in detail. All the 

 larvae, from birth, secrete from a projection of the hypopharynx, on the in- 

 ferior surface of the buccal funnel, an abundant salivary hquid, which at 

 the slightest touch spreads over the mouth in a drop. All the adult wasps, 



