THE ARGENTINE ANT : DISTRIBUTION AND CONTROL. 7 



January, and February (at New Orleans) these large colonies are 

 found. They sometimes reach very extensive proportions and may 

 contain several hundred queens and countless workers and immature 

 stages. These colonies are usually located at the base of large trees 

 on high, well-drained spots of ground, in manure piles, or in any other 

 piles of decomposing rubbish where heat is generated. A warm day 

 will make them particularly active, and they will form trails in all 

 directions from these winter nests to food supplies. They may be 

 observed traversing the trunks of trees every warm winter day, and 

 from the trees trails are made to nearby houses, where they cause 

 considerable annoyance. 



With the advent of warm spring weather the breaking up of the 

 large colonies occurs. This is the time of the year that food is very 

 scarce, and at this season the ants are particularly aggressive and 

 troublesome in the houses. This is the best time to use poisoned sirup, 

 which will be described later, for controlling this pest. 



LIFE HISTORY. 



There are three adult forms to be found within a complete nest in 

 the spring months of the year the queen, the male, and the worker. 

 A colony may be complete, however, with a queen and workers. 

 Three immature forms are also present the egg, larva, and pupa. 



EGG. 



In an artificial formicary a fertilized queen lays from 3 to 30 eggs 

 per day when ample food is supplied. It is very probable that under 

 natural conditions the egg production is considerably more. Only a 

 few seconds are occupied for the laying of each egg. A worker, 

 apparently awaiting the arrival of the egg, picks it up and transfers 

 it to a pile of eggs already in the nest. The surface of the egg is 

 somewhat mucilaginous and readily sticks to other eggs. This per- 

 mits the workers to handle the eggs en masse and also permits of 

 their being deposited in desirable locations on the walls and ceilings 

 of the galleries. 



The egg when first laid is about 0.3 mm. long and 0.2 mm. wide. 

 It is elliptical, pearly white, lustrous, and without markings. As the 

 time for hatching approaches the luster disappears. It is extremely 

 difficult to detect the exact time of hatching. The average summer 

 incubation period is about 15 days, but this, of course, is subject to 

 the variations of temperature and humidity during this period. 



LARVA. 



The larva, when first hatched, is creamy white. Its body is very 

 curved, but it gradually straightens as the larval growth continues. 

 It is entirely helpless and is practically motionless. 



