1907.] Wheeler, Fungus-growing Ants of North America. 791 



of sublimed sulphur. The brood chamber is packed at times with eggs, 

 larvae, pupse and adults in all stages of maturity. The larvae aid in extend- 

 ing the brood chamber. They swallow the wood which they remove with 

 their jaws, and in passing through their bodies it becomes stained a mustard- 

 yellow color. Great quantities of this excrement are ejected from the open- 

 ings of the colony, but a portion is retained and plastered upon the walls, 

 where it serves as a bed upon which there springs up a new crop of the food 

 fungus. In populous colonies it is not unusual to find the remains of individ- 

 uals which have died packed away in a deep recess of the brood chamber 

 and carefully inclosed with a wall of chips." Hubbard found one of these 

 catacombs containing "the multilated bodies of a dozen or more larvae 

 and immature imagoes, together with the fragments of a predatory beetle, 

 CoJydium lineola Say." In a short branch gallery of the same chamber he 

 also found the lifeless body of the mother of the colony carefully sealed up 

 by the surviving insects. 



In the species of Pterocyclon, Xyloherus and Gnathotrichusi\\<ijo\xng2ixe 

 reared in cradles, or short diverticula of the main galleries, and fed by the 

 mother beetles. In species of Ptercyclon {mail Fitch and fasciatum Say) 

 "the sexes are alike, and the males assist the females in forming new colonies. 

 The young are raised in separate pits or cradles which they never leave until 

 they reach the adult stage. The galleries, constructed by the mature 

 female beetles, extend rather deeply into the wood, with their branches 

 mostly in a horizontal plane. The mother beetle deposits her eggs singly 

 in circular pits which she excavates in the gallery in two opposite series, 

 parallel with the grain of the wood. The eggs are loosely packed in the 

 pits with chips and material taken from the fungus bed which she has pre- 

 viously prepared in the vicinity and upon which the ambrosia has begun to 

 grow. The young larvae, as soon as they hatch out, eat the fungus from these 

 chips and eject the refuse from their cradles. At first they lie curled up in 

 the pit made by the mother, but as they grow larger, with their own jaws 

 they deepen their cradles, until, at full growth, they slightly exceed the 

 length of the larvae when fully extended. The larvae swallow the wood 

 which they excavate, but do not digest it. It passes through the intestines 

 unchanged in cellular texture, but cemented by the excrement into pellets 

 and stained a yellowish color. The pellets of excrement are not allowed 

 by the larvae to accumulate in their cradles, Init are frequently ejected by 

 them and are removed and cast out of the mouth of the borings by the 

 mother beetle. A portion of the excrement is evidently utilized to form the 

 fungus bed. The mother beetle is constantly in attendance upon her young 

 during the period of their development, and guards them with jealous care. 

 The mouth of each cradle is closed with a jjlug of the food fungus, and as 



