136 NOTES UPON THE FORMICID^E OF MACKAY, 



only throw them backwards clean out of the cup but sometimes 

 full}' a foot beyond it. Wishing to see how they laid hold of 

 anything, I let the end of a piece of string hang down into the 

 cup, but they closed their jaws slowly in a somewhat aimless 

 manner as if they did not understand escaping by this means. 



The moment a nest of this species is disturbed, the woi'kers 

 come rushing out, making a curious squeaking noise quite 

 distinct from the sound caused when the jaws snap together. 

 This is the only ant that I have come across that emits a true 

 sound audible to the human ear, but as yet I have not been able 

 to ascertain how this sound is produced. 



Parasitic hymenoptera (Family Ghalcididce) are sometimes met 

 with in ants' nests; once when breaking up a rotten log contain- 

 ing a nest of Pheidole variabilis, Mayr, a fine specimen of 

 jEiicluD'is sp., just ready to emerge, was found among the ants. 

 In another case, four ant pupte enveloped in their silken cases 

 wei'e found in the nest of Bothroponera mayri, Em., and placed 

 in a breeding bottle, where they remained from September to the 

 middle of November, when a fine female chalcid of the genus 

 R}iij)ipallus emerged from one, though it was not until three 

 months later that the ants came out of the other three pupa 

 cases. 



Of the genus Both roj) on era there are three or four large species 

 which resemble each other very closely, and the individuals 

 of which, when disturbed, discharge a white frothy substance 

 from the anus ; though when they sting, which they do pretty 

 severely, they do not eject this frothy matter. 



In collecting ants, spiders are frequently met with that not 

 only closely resemble the ants among which they consort, both in 

 form and colouration, but also in their mode of progression, so 

 that it is only after their capture that their true affinities are 

 revealed. 



One spider takes to itself the appearance of a worker of 

 Jjeptomyrmex erythrocepJialus, Fabr., and curves its abdomen 

 upwards and forwards until it rests on the top of the thorax, 

 exactly the same as the ant; another bears a very strong resem- 



