25 



thickness of the bodies of the adult beetles. The larvae of all i 

 are able to cling to the vertical walls, and to progress over them by 

 an adaptation of the end of the body which aids them in progression. 



The entire surfaces of the walls in the brood chamber are plastered 

 over with ambrosia fungus, a representation of which is given in fig 

 It consists of short erect stems, terminating in spherical conidia. 



Fig. 22. — Gallery of Xyleborus xylographtu in hickory : a. b. death chambers (original). 



The freshly grown fungus is as colorless as crystal, but it is usually 

 more or less stained with greenish-yellow, and sometimes resembles a 

 coating of sublimed sulphur. The brood chamber is packed at times 

 with eggs, larvae, pupae, 

 and adults in all stages 

 of maturity. The larvae 

 aid in extending the brood 

 chamber. They swallow 

 the wood which they re- 

 move 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 openings 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 recessof the brood cham- 

 ber and carefully inclosed with a wall of chips In fig. 22, at a, is 

 shown such a catacomb, which was found to contain the mutilated 



i 



Ambrosia ■ ■: ' .-_.''•.<.. 



; oal). 



