i.S4 ANTS. 



siinilliiintiii, rrcnolcpis fulra and lont^icornis, 

 Tapinonia melanocephalum and Iridomyrmex hmnilis. All of these, 

 with the exception of the pavement ant (T. cespitum), are of tropical 

 origin, ajid nearly all of them have come from the Old World. T. 

 ccspiiuni of Kurope is now common about New York, Washington 

 and Philadelphia, but it is so sporadic that we must conclude either 

 that it is of comparatively recent importation, or is prevented from 

 spreading bv competition with our native ants. 1 



All of the other species cited above require considerable warmth 

 and even Monomorium pharaonis, the tiny yellow house-ant, which is 

 often a pest in ships or in the dwellings of sea-port towns, does not 

 nest out of doors except in southern latitudes. Some of our tropical 

 ants (Ncoponcra z'illosa, Camponotns floridanns and Phcidole flavens} 

 manage to live for considerable periods of time in our northern hot- 

 houses. At least one species from the American tropics {Iridomyrmex 

 Iiiunilis (Fig. 86)) has acquired a much wider range, having recently 

 made its appearance in New Orleans. In this locality, where its habits 

 have been carefully studied by Titus (1905) and Newell (19080), it has 

 become a serious pest and is driving out the native ants. That it is 

 spreading rapidly over the warmer portions of the globe is shown by 

 the fact that I have recently received specimens from various locali- 

 ties in California and from Cape Colon}-. It has also become a pest 

 in Portugal (Martins, 1907), and, according to Stoll (1898) has been 

 imported into Madeira where it has supplanted another previously 

 introduced species, Phcidole megacephala, which was the house-ant of 

 the island in the days of Heer (1852). 



Some idea of the abundance of this ant in the middle of the last 

 century may be gained from the following extract from Heer's work : 

 ' It occurs throughout the southern portion of the island of Madeira 

 up to an elevation of i.ooo feet in prodigious numbers, especially in 

 hot, sunny places, where it is to be found under eight out of every 

 ten stones that may be overturned. In the city of Funchal there is 

 "probably not a single house that is not infested with millions of these 

 insects. They climb to the top stories, issue in swarms from the cracks 

 in walls and floors and keep crossing the rooms in regular files in all 

 directions. They creep up the legs of tables, along their edges and 

 into cupboards, chests, etc-" This ant is very common in the Ber- 

 mudas and West Indies and will probably be found in Florida. There 

 can be little doubt that wherever it gains a foothold in tropical or 



1 According to Marlatt (1898) this species has long been a resident of the 

 Eastern States. He believes that it may be the species referred to by Kalm 

 as occurring in the houses of Philadelphia as early as 1748. 



