CONTKOL OF ARGENTINE ANT IN CALIFORNIA. 7 



sion of the colony usually occurs in the early spring and summer 

 months. In the late fall (November) the outpost communities are 

 usually abandoned and large central winter colonies are formed in 

 more favorable locations having better drainage and sun exposures. 

 The activities in these communities are limited, fewer workers are 

 sent out in search of food, the male form disappears, reproduction 

 almost ceases, and the number of ants is reduced. Several colonies 

 dug up in December, 1919, and January, 1920, showed a large num- 

 ber of workers in the colony with only a light trail going out in search 

 of food, a number of females, no males, few if any eggs, a few matured 

 larvse, and numbers of pupae. Renewed activities in these colonies 

 and the division of the central colony usually occur in early April, 

 though the time may vary somewhat with the season. 



As stated, the summer colony is composed of three distinct forms 

 of adults — workers, males, and queens. (See fig. 3.) The workers 

 gather the food and attend to the labors of the community and are 

 simply imperfect females with no reproductive capacity. They 

 greatly outnumber the other forms and are the ones most commonly 

 met with. The males, always winged, are the drones of the colony 

 and have only one function, that of fertilizing the queen. The queens 

 are the reproducing females and for a short time during the mating 

 period are winged. They remain in the nest most of the time, but 

 occasionally may be found out in the trails — a characteristic of this 

 species (fig. 4). It is absolutely necessary that a fertilized queen ac- 

 company a number of workers if a new colony is to be established, as 

 the workers alone have no means of reproduction. 



The winters in southern California, though occasionally wet enough 

 to retard the development of the ant colonies and force them to win- 

 ter quarters, are so often broken by short, warm spells and the aver- 

 age rainfall is so light that trap nesting has proved ineffective and 

 seldom are any of the colonies destroyed by excessive moisture. 



The preferred food of the ants in orchards is the honeydew secreted 

 by certain scales and apliids, the honeydew from blossoms, and the 

 bodies of certain soft-bodied insects. The workers are very active in 

 cdlleclfeing this food and may be observed returning along the trail 

 from a foraging expedition, their abdomens greatly distended with 

 liquid food, or their strong mandibles securely clasping their prey. 

 About residences the ants are more or less scavengers, feeding on bits 

 of food wherever they can find it. but frequently invading pantries 

 and even ice chests in search of moats, sugar, sirups, fruit, etc. Their 

 trails may be extended to any part of the building in search of food 

 and often during the first few hot days of summer the ants stomi 

 the house. 



An interesting feature in the distribution of this ant is that it has 

 completely replaced all native species, with possibly two exceptions, 



