22 BULLETIN 377, U. S. DEPARTMENT OF AGRICULTURE. 



the cans may be hung on trees, fences, walls of houses, etc. The ants 

 prefer to climb for their food, and it is well to hang the cans near ant 

 trails going up trees, walls, etc. It is advisable to hang the cans in 

 the shade to prevent the evaporation of the sirup, for though it has 

 been proved that evaporation does not affect this sirup to a marked 

 extent, it is well to avoid raising the solid contents of the liquid. 

 Eight to ten of these cans should be sufficient to place around an 

 ordinary city house and lot. If the grounds are large and if many 

 trees are present, more cans should be placed out. 



From the results so far obtained, the careful preparation of the 

 poisoned sirup can not be too highly emphasized. Very accurate 

 balances are necessary for the weighing out of the poison and the 

 tartaric acid. This is especially true when small quantities of the 

 sirup are prepared. 



PLANS FOR MUNICIPAL CONTROL WORK. 



In effecting control in towns and cities it is first necessary to ascer- 

 tain the extent of the infestation. This should be mapped out so that 

 workmen in distributing the cans will be able to refer to the map to 

 insure the covering of the entire territory. Cans may be obtained at 

 wholesale at about $16 per thousand. About 10 pounds of " grass " 

 sponges will be required per 1,000 cans. These will cost about 75 

 cents per pound. The sponges should be thoroughly washed and dried 

 before use. When wet they may easily be torn into pieces about 

 2 by 2 inches. Using 1 gill of sirup per can, 200 pounds of granu- 

 lated sugar will be required per 1,000 cans. The cost of the sodium 

 arsenite is about 80 cents per pound, and 1 pound will be sufficient 

 for 1,500 cans. Tartaric acid (crystallised) costs about TO cents a 

 pound, which will be enough for 4,500 caws. From 60 to 100 cans 

 will be required per block, depending on the size of the block. The 

 late fall, \vinter, and spring are the most desirable times in which to 

 do this work, as in these seasons the natural food is least plentiful 

 and the ants most hungry. Two men should be able to prepare the 

 sirup, wash and tear up the sponges, and charge about 2,000 cans per 

 day and distribute about 1,000 cans per day. 



TRAPPING ANTS. 



By taking advantage of their winter colonizing habit the ants may 

 be attracted in large numbers to specially prepared trap boxes, which 

 may be fumigated when large numbers have gathered in these boxes 

 for winter nesting. Newell and Barber, who originated this method 

 of control, describe in Bureau of Entomology Bulletin 122 some very 

 interesting and successful trap-box experiments. The boxes were 

 filled with decaying vegetation, the heat generated making them very 

 attractive as hibernating quarters. Carbon bisulphid was found to 



