OKTHOPTEEA OF INDIANA. 417 



they set foot on the floor of the nest. Their adaptation to a new 

 nest and to an ant of a larger size and belonging to an entirely dif- 

 ferent snb-family from their former host, was immediate and com- 

 plete. With constantly vibrating antennae they began dodging in 

 and out among the little groups of assembled ants. From time to 

 time one of them would be seen cautiously approaching an ant, that 

 was busy with its dinner of Myrmeeophila, and fall to nibbling at its 

 legs or the tip of its abdomen. There could be no doubt that the 

 cricket derived some benefit from the oily secretion covering the sur- 

 face of the ant's body. At first the ant disregarded this nibbling, 

 which probably resembles the attentions of the toilet habitually re- 

 ceived from sister ants, but the cricket's scraping mandibles and 

 maxillae soon grew annoying and the ant would either move away 

 or turn its head, open its mandibles and make a lunge at the Myrme- 

 eophila like a large dog annoyed by a puppy. But before the huge 

 mandibles had closed, the cricket was far away, already nibbling at 

 the abdomen of some other ant. The Cricket can get at only the 

 legs and abdomen of its host, since the spreading legs prevent it 

 from reaching the thorax. It often stands on its hind legs, and 

 places its forelegs on the ant's leg, in order to reach the femur or 

 tibia. For very obvious reasons, it avoids nibbling at or even ap- 

 proaching the ant's head. It is always alert, as if perpetually aware 

 of danger and ready to dodge at the slightest movement made by 

 the ant. 



"Occasionally in the narrow confines of an artificial nest the ants 

 do succeed in capturing and devouring one of their vigilant little 

 guests, but the fact that of the eleven sound crickets left after the 

 above observation was made, eight were still alive June 22d, when I 

 had to discontinue my observations for the summer, shows that the 

 crickets are extremely expert in keeping out of danger. The atti- 

 tude of the ants during all this time underwent no change as far as 

 I could observe, for they would still occasionally make lunges at the 

 crickets. 



"The crickets do not derive all their substance from cleansing 

 their hosts. In earthen nests tliey are often seen haunting even the 

 galleries that have been abandoned by the ants, scrutinizing the 

 walls and nibbling at them from time to time. There can be no 

 doubt that they find licre the same substance which covers the ants, 

 for the walls of the galleries of a populous nest soon become greasy 

 from the attrition of tlie constantly passing ants. Sometimes the 

 crickets may be seen nibbling at dead ants that have been tempor- 

 arily al)andon('(l in tlic galleries or placed on the kitchen-midden of 



