WILD LIFE *N CALIFORNIA 



29 



pyrethrum are offensive and death dealing to 

 the Argentines and by a liberal use of the 

 powders we can protect our homes from be- 

 ing overrun, and with care, attention and 

 continued use of the powders we can keep 

 the annoyance reduced to the minimum. 



Has the Iridomyrmex come to stay? Will 

 it continue to be a pest of our homes for all 

 time to come? These questions could be best 

 answered by some such authority as Profes- 

 sor W. M. Wheeler, who has made a life 

 study of ant family. It is not beyond a pos- 

 sibility that some species of pupae-eating ant 

 or some other order of predaceous insect 

 might be introduced here that would hunt out 

 and invade the nests of the pest ants and 

 exterminate the colonies by devouring the 

 young, just as the Argentines have done in 

 exterminating about all other species of ants 

 that were common about our gardens and 

 homes a few years ago. This suggestion, 

 however, does n/>t hold out much hope of 

 relief. Nor does the possibility that the 

 pests may be attacked by entomophthoreae 

 fungi that at times spread among various 

 forms of insect life, causing great fatality. 

 There are several species of the fungus, but 

 the life history of each is much the same. The 

 germs, or spores, which are extremely minute 

 are supposed to find their way to the inter- 

 nal parts of the insect by being on or in the 

 food which the latter eats. Once inside the 

 fungus begins to develop from the spore and 

 as its parts absorb the interior organs the 

 insect suffers a slow death. ' Soon after 

 death occurs the fungus makes its appear- 

 ance on the outer parts of the victim. Some 

 species send stems of shoots several inches in 

 length out from the head, thorax or other 

 parts of the body while other kinds of fungi 

 can be recognized only on the exterior of the 

 unfortunates by the whiteish powdery ap- 

 pearance of a rapid growth. A common ex- 

 ample of this species and its work is the 

 ordinary house fly that we sometimes see 

 dead upon the windowpane appearing as if 

 it had just escaped from a flour barrel. 



But while hoping for an enemy insect or 

 the fungi to relieve us of the pest, the house- 

 wife cannot relax in the use of boiling water 

 and insect poisons to keep the ants reduced 

 to the smallest number; besides giving trial 

 to every reasonable suggestion for the ex- 

 termination of the invaders. These thoughts 

 prompted me to look up suggestions made by 

 the best authorities on fighting insect pests, 

 when I found that W. Newell, a student of 

 this particular nuisance, recommends a "trap 

 made in form of a box 2x2x3 feet, filled with 

 cotton-seed and straw on other porous vege- 

 table material. The top of the box is left 

 open so that its contents are exposed to the 

 weather. The interior of the compost mass 

 becomes warm through decomposition, and 

 as winter approaches attracts the ant colonies. 

 During the month of January, after the col- 

 onies have assembled in the box, its cracks 

 are closed, a pound or two of carbon bi- 

 sulphide is poured into the compost and the 

 whole is covered with a waterproof canvas 

 till the ants are asphyxiated." 



Another plan which neighbors have tried 

 and found very effective, is to put pieces of 

 sponge saturated with sweetened ant poison 

 in perforated tin cans and then place these 

 cans ten or fifteen feet apart around the 

 basement of the house on the ground outside. 

 The theory of this scheme is that the ants, 

 which generally live outside of the houses, 

 will be attracted to the poisoned food before 

 invading the interiors. If the ants are not 

 killed by the poison, the generous supply of 

 food makes it unnecessary for them to go 

 farther. Of course, the supply of poison must 

 be kept up in the sponges. 



The Argentine ants have found homes in 

 this country in and about two seaports of 

 the United States — San Francisco and New 

 Orleans. It is a matter of interest to know 

 how these pests, whose nativity or place of 

 origin is South America, managed to get es- 

 tablished in this part of the world. It is easy 

 to understand how numbers of ants might be 

 brought here in merchandise shipped from 

 the distant ports of the South, but when we 

 contemplate the fact that colonies of these 

 ants are made up of Queens, males and work- 

 ers, the latter of which are neuters and are 

 about the only ants in evidence unless we can 

 unearth their nests in which the two former 

 remain until mating season, the transplanting 

 has some complex features. 



A peculiarity of the Argentines is that unlike 

 most other genera of ants, the male instead of 

 the queen is the winged ant, as shown in the 

 illustration. 



No work on mymexcology at my disposal 

 gives the details of the life history of this 

 particular genus of ants, but in nearly all 

 other genera of ants with similarly constituted 

 colonies, new nests or colonies are started by 

 young queens which leave the parent nest 

 upon being fertilized, and the queen ants 

 are winged when they emerge from the pupae 

 state. Thus they are enabled to fly to some 

 distance from their former abode. When 

 they alight about the first thing they do is to 

 bite off or remove their wings, these append- 

 ages being wholly useless to them in all situa- 

 tions of their future life. They then seek 

 some favorable place in the ground, under 

 rocks, wood or chinks in masonry in which to 

 start a nest. There they lay a lot of eggs and 

 raise the first brood, feeding and caring for 

 them with all attention and anxieties usually 

 manifested by mothers of higher order of life. 

 As a rule, this first brood consists of workers 

 which take up the care of the nest and future 

 hatchings, and the queen has" no other duty 

 than to remain in the nest and lay eggs. 



With this order of life in view, it would 

 seem that queen ants must have been in some 

 manner transported from South America to 

 this country. However, Wasmann, an ento- 

 mologist of note, found in oue species of ant 

 that he had under observation that "one or 

 a few workers became gynaecoid"; that is, 

 became egg-laying workers, and fulfilled the 

 duties of the absent queen. If this peculiarity 

 is a feature in the life history of the Argentine 

 ant, the riddle would be explained. Perhaps 



