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C. H. TURNER. 



E (Fig. i) with dissecting needles and glass rods. Sometimes I 

 used plain needles or glass rods, at others needles or rods that had 

 been moistened with oil of cedar or oil of cloves. Each time the 

 fight was continued until the ant retreated into the innermost part 

 of the nest. After these maneuvers had been repeated several 

 times daily for about a week, the guard withdrew from the entrance 

 i; and the ants plugged that passage-way with detritus, composed 

 of bits of wood and bread from the island, trash from the interior 



Fig. i. 



of the neit and cotton stripped from the turkish toweling of the 

 nest. For five months . thereafter the nest was examined from 

 five to ten times every day, but no ant was observed as a guard, 

 in either entrance E or the tunnels connecting the apartments 

 until August 10, 1907. Since then they have been mounting 

 guard as regularly as they did before they plugged the entrance. 

 On the same Lubbock island with the above-mentioned Cam- 

 ponotiis-lierciilea7io-ligniperdiis, I had a large colony of Formica 

 fusca var. subsericea Say. The island was kept littered with de- 

 tritus of various kinds. One day I noticed a worker of this 

 colony begin the construction of a bridge across the ditch of 

 water that surrounded the island on which the colony was located. 

 This partial bridge was constructed in the following manner. The 

 ant placed a piece of charred paper about one centimeter wide 



