INSECTS AFFECTING PARK AND WOODLAND TREES 



291 



males assist the females in forming new colonies, and that the young are 

 raised in separate pits or cradles which they do not leave until maturity is 

 attained. The galleries constructeil by the female beetle, extend deeply 

 into the wood with their branches mostly in a horizontal plane, figure 53. ' 

 The mother beetle deposits her eggs in circular pits which she excavates in 

 the galleries in two opposite series parallel with the grain of the wood. 

 An e^^g is deposited in each and the cavity packed with chips taken from 

 the fungus bed on which ambrosia had begun to grow. The young grubs 

 eat the fungus 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 they 

 deepen the cradles with their own jaws till when full grown they slightly 

 exceed the length of the full)' extended grub. The young swallow the 

 wood which they excavate. It passes through the body unchanged in 

 texture and is excreted in pellets stained 

 a yellowish color. A portion of the excre- 

 ment is evidently utilized to form the 

 fungus or food bed. The mother beetle 

 is constantly in attendance on the young 

 during their developmental period and 

 guards them with jealous care. The 

 mouth of each cradle is closed with a 

 plug of the food fungus and as fast as 

 this is consumed fresh material is sup- 

 plied. The grubs perforate the plug 

 from time to time and clean out their 

 retreats by pushing the pellets through 

 the openino-. They are removed by the F'g- 54 Ambrosiaof Monanh rum maii, greatly 



' '^ "^ _ _ ■' enlarged. (After Hubbard. U. S. Dep't Agric. Div. 



mother, and the opening again sealed Em. bul,, ,.. s. .so?! 



with ambrosia. The transformation to the adult occurs in these lateral 



galleries or cradles. 



Mr Hubbard states that the habits of Monarthrum fasciatum 

 Say and those of this insect are identical and that they feed on the same 



