228 



BARK-BEETLES ; ENGRAVER-BEETLES. 



in spherical conidia. The freshly grown fungus is colorless as 

 crystal, but it is usually more or less stained with greenish-yellow, 

 and sometimes looks like a coating of sublimed sulphur. The 

 brood chamber is at times packed 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 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 openings of the colony, but a portion is retained 

 and plastered on the walls, where it serves as a bed upon which a 

 new crop of the fungus springs up. In populous colonies it is not 

 unusual to find the remains of individuals who have died packed 

 away in a deep recess of the brood chamber, carefully enclosed 



Fig. 24-2. — Xvleborus xylographus, Say; female and male. After Division of 

 Entomology, U". S. Department of Agriculture. 



with a wall of chips. At a in Fig. 240 such a catacomb is shown, 

 which was found to contain the mutilated bodies of a dozen or 

 more larvae and immature imagos, together with the fragments 

 of a predatory beetle, Colidium lincola Say. This tomb bears tes- 

 timony to a sanguinary conflict in which victory crowned the 

 efforts of the ambrosia beetles. The bodies of the slain, both 

 friend and foe, have been consigned to the same sepulchre. In 

 the same figure, at b, a short branch of the gallery is shown con- 

 taining the lifeless body of the mother of the colony, who appears 

 to have constructed her own tomb, and to have crawled into it as 

 she neared her end. The mouth of this tomb has also been sealed 



