44 



THE ARGENTINE ANT. 



the workers, and the pupal skm, or at least a portion of it, is worked 

 backward to the tip of the abdomen and there shed entirely. Within 

 a few hours after transformation the wings of the male become fully 

 expanded. The following table shows the duration of the male pupal 

 stage at different seasons. 



Table Y. — Duration of pupal stage of the Argentine ant, individual males, 1908. 



' Average days, 2:iJ. 



The normal time of appearance of the male pupse is in the spring, 

 but the appearance of a relatively small number in autumn is not 

 uncommon. During April and ^lay they are usually abundant, 

 gradually disappearing in the latter part of May and early June. 

 Only in one case have they been observed in midsummer, when three 

 or four male pupae were found at Baton Rouge, July 24, 1909, in a 

 huge nest which contained thousands of immature stages. 



THE QUEEN PUPA. 



The pupa which is to become a queen is readily distinguished from 

 the male or worker pupa by its size, as it is considerably larger than 

 the male and more than twice as large as the worker pupa. The 

 whole body is more uniformly developed than in the case of the male 

 pupa. The head and thorax are not nearly so large in proportion to 

 the rest of the body, the abdomen is much larger, and the dividing 

 line between head and thorax is much more distinct. Apart from its 

 size the queen pupa is readily recognized l)y the presence of the promi- 

 nent \ving pads. 



Queen pupjB have been found onl}?" during April and May. The 

 duration of this stage has not been worked out, as we have not been 

 fortunate enough to secure larvie which would transform into queen 

 pupae in our cages. Considerable numbers of these pupae have, how- 

 ever, been collected in the field by the junior author and have been 

 reared to the adult stage in the artificial formicaries, observations on 

 them extending over a period of two weeks. The queen pupal stage 



