CHAPTER FORTY 



ANTS 



1. ANTS have always attracted the attention of man- Characters 

 kind on account of their abundance, wide distribu- 

 tion, and social habits. They constitute a group of the 



order Hymenoptera, and are especially distinguished 

 by the structure of the abdomen or hind body, which 

 has one or two modified basal joints, forming nodes or 

 scalelike structures. It will also be noticed that the 

 antennae are elbowed or sharply bent, superficially ap- 

 pearing as if broken. Nearly all ants exist in three 

 forms, the male, female, and worker. The male and 

 female have wings, but the latter removes her wings 

 when she has been fertilized and is about to start a 

 nest. The workers, which are sterile females, are 

 entirely wingless. The sting in ants, bees, and wasps 

 represents and is derived from the ovipositor which 

 exists in more primitive groups. This ovipositor, or 

 egg placer, naturally belongs to the female ; hence 

 male Hymenoptera do not sting. Among the ants, 

 the workers of many genera, being modified females, 

 can sting; but in many other genera this power is lost. 



2. Polymorphism is the name given to indicate the Poiymor- 

 existence of several different forms within the limits 



of a species. If there are only two forms, - - for in- 

 stance, two sexes differing in appearance, - we speak 

 of dimorphism. When there are three forms, as male, 

 female, and worker, the term trimorphism may be 

 used. Beyond this comes polymorphism, from the Greek 

 words meaning " many forms." We also use the adjecti- 

 val forms polymorphic, dimorphic, trimorphic. Ants are 

 often highly polymorphic. Frequently the workers 

 differ greatly in size, and in some species there is a 



299 



