8 



back into the egg-shell, but now they are pushed out through 

 the circular hole thus made. Working now down the center of 

 the twig and continually enlarging its burrow, the larva pro- 

 vides at intervals similar but larger vents in the walls for the 

 same purpose. In this species these holes for the disposal of 

 excreta and waste material do not appear to be as frequently 

 cut as in the case of allied species, the distance from one to an- 

 other ranging in our specimens from a little over an inch to 

 more than two inches. 



Several years ago, while studying similar habits of what I 

 then supposed to be Oberea bimaculata, but now know to have 

 been O.tripunctata, I observed these holes to occur frequently not 

 more than an inch apart, and the excreta were pushed through 

 and fell down in more or less continuous sections. In two cases 

 the masses of excreta thus disposed of by a larva of that species 

 nearly full grown and about an inch in length during the twenty- 

 four hours, were kept and carefully measured. Their length 

 amounted to the astounding total of twenty-four and three 

 eighths inches, showing that each hour of the day and night the 

 larva had voided a stool greater than its own length, — a fact 

 which gives some idea of the enormous amount of food eaten 

 within that time.* 



As the larva increases in size it frequently reverses its posi- 

 tion in its burrow, and moves up and down at will. These 

 journeys are easily accomplished by the simple contraction and 

 expansion of the segments of its body aided by the shagreened 

 areas on the dorsal surface. Just prior to pupation, the larva 

 gnaws out a cavity in the wall of its burrow similar to that 

 constructed for the disposal of the excreta, except that it does 

 not penetrate the outer bark. An avenue of escape is thus pro- 

 vided for the adult beetle without exposing the pupa. Pupation 

 occurs within the burrow, and only a few minutes are required 

 for the escape of the beetle from the pupal envelope. 



Secure as they may appear to be in their channels, the 

 larvae are not without their troubles, for not only the main 



*Journ. N. Y. Ent. Soc, Vol. V., pp. 202-203, PI- X., Fig. 1 and 2. 



