180 JOURNAL OF THE TRINIDAD 



Genus : Apterostioma, Mayr. 



A. urichii, Forel, n. sp. 



Moller suggests the name of "Hairy Ants " for this genus 

 on account of the long hairs covering their bodies. Unlike 

 Atta this species does not excavate its nests but builds them in 

 rotten trunks of trees in any dark crevice it can find. I suc- 

 ceeded in securing several nests intact without destroying their 

 structure. They are built in a hanging position i.e. the ants start 

 working from the top, but never let the nest touch the bottom 

 of the cavity. Unless the garden is quite recent and small, it is 

 always enclosed in a delicate white covering, which on first sight 

 looks like fine cobweb, with an exit hole at the bottom. The 

 nests therefore look like a more or less round ball and are never 

 larger than an apple. On breaking away this delicate covering 

 a small mushroom garden is found consisting of irregular cells 

 in which the ants, larvse and pupae, are scattered. It is at once 

 apparent that the inhabitants are also mushroom growers and 

 eaters, and a microscopical examination reveals the fact that 

 they have a fungus like Atta, belonging apparently, according to 

 Moller, to a different genus of liozites. The chief point of 

 interest however is that they have not cultivated and selected the 

 " kohlrabbi " to the same degree as Atta. Their " kohlrabbi " is of 

 lower type, the hyplme being only slightly swollen into a club 

 shape instead of being large and spherical, and they are not aggre- 

 gated into groups. An examination of the covering shows it to 

 be a fabric woven with the mycelium of the same fungus which 

 holds the cells together. The ants, no doubt, arrange and regulate 

 the growth of this covering, with their legs and antennae. As I 

 said before the gardens are always found under rotten wood and 

 the ants invariably use the excrementa of wood-boring insects as 

 a medium for growing their fungus on. I have kept these ants 

 in captivity, but never with much success as they will not 

 touch fruit, flowers or leaves. They took excrementa of wood- 

 boring insects readily and cassava farine sparingly. From an 

 economic point of view, they are therefore (mite harmless. The 

 colonies of these ants are small, not numbering more than 20 or 

 30 dark brown workers, all of about the same size viz. 6-6^ mm. 

 and with abnormally long legs which measure 7-7J mm. without 

 the hip. They are of nocturnal habits. 



A. mayri, Forel, n. sp. 



This species can be readily recognized from A. urichii 

 by its smaller size. The workers measure 3— 3| mm., but 

 are of the same colour and also covered with hairs. They 

 are mushroom growers and eaters and construct hanging gardens, 



