FIELD NATURALISTS' CLUB. 1/7 



fond of our cultivated Cocoa. On some nests I have seen a large 

 quantity of freshly cut leaves while on others there is no such 

 deposit. In an artificial colony the ants deposited leaves outside 

 the nest, as long as there was not any available room inside, and 

 used them by degrees. Some weeks later the nest diminished con- 

 siderably and the ants no longer left leaves outside, as there 

 was room in the interior, where they were deposited and used 

 up by degrees. The roads these ants make in the woods are well 

 known and have been ably described by Bates, Belt and other 

 travellers in Tropical America. Now as to the inhabitants of 

 the gardens ; there are six distinct kinds of workers or neuters 

 the smallest being 2 m.m. in length and the largest, or soldiers, 

 15 mm. The smallest workers perform the duties of nurses to 

 the larvae and also weed the garden " and this is so well done 

 " that a portion of it removed and grown in a nutrient solution 

 "gives a perfectly pure culture, not even containing bacteria ; " 

 they also go out with the leaf cutting gangs and are carried 

 home on the pieces of leaves. They do not seem to take any 

 part in cutting the leaves and I cannot find out why the}' go, 

 unless it is because the ant doctor orders the nurses sometimes 

 to leave their troublesome charges and take the ant equivalent of 

 carriage or equestrian exercise. Those varying from three to 

 six mm. are the foragers which do us the damage by cutting the 

 leaves. Those from six to fifteen mm. are the soldiers or light- 

 ing ants. Their only use is the defence of the nest, and for this 

 purpose they have strongly developed pairs of mandibles and a 

 very large head. They cannnot sting, but draw blood at each bite. 

 They accompany the foragers or leaf cutters, marching on the 

 Hanks of the column. Their mandibles close like scissors and are 

 toothed, but these teeth, when viewed under a high power do not 

 appear to be pointed but are more like the edge of the new 

 fashioned bread knives which are so largely advertised just now. 

 The tips of the mandibles overlap when closed. Of all the Attn 

 species in Trinidad cephalotes is the most energetic and in the 

 woods work day and night, but in the cocoa groves they only 

 sally out after dark. Winged forms arc found in the nest from 

 May to July ami this is the best time for killing them. 



Subgenus : Acromyrmex, Forel 



A. oclospincsa, Reich. 

 = A. Giintlwri, Forel. 



In the same way that Atta cephalotes is the terror of the 

 country people this species is a regular plague to gardens, even 

 those situated in the heart of the town. They also occur in the 

 country districts. They do not form such large colonies as do 

 the preceding ones, but they form small nests from \ to 1 

 cubic foot in clayey soil which they excavate, but they readily 



