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NEW YORK STATE MUSEUM 



Fig. 8 Ambrosia of Corthylus punctatis- 

 simus. A detached dumb-bell-shaped pair ol 

 cells, greatly enlarged. (After Hubbard, U. S, 

 Dep't Agric. Div. Ent. Bui. 7, n. s. p. 97) 



He states that the entrance hole leads into a circular gallery, the far- 

 thest end of which is always a little above or below the point of 

 attack. From this circular burrow a varying number of straight, short 



galleries lead perpendicularly either upward 

 or downward. Sometimes the beetle exca- 

 vates below from the point of entrance 

 and at other times above ; in some cases 

 there may be as many as three circular 

 galleries one above the other, and in almost 

 every instance they are at or below the 

 surface of the ground. Dr Schwarz calls 

 attention to a novel feature in that this 

 insect sometimes constructs a straight gal- 

 lery through the core or heart of the root, 

 beginning at the top of the honeycombed portion and carrying it upward, 

 sometimes above the surface of the soil. This is believed to be a 

 hibernating gallery which the insects make in order to 

 secure a dry place, where they can spend the winter. 

 The small' diameter of huckleberry roots as compared 

 with those of maple, makes' it very difficult for the 

 insect to follow the usual plan, and as a consequence 

 the galleries are more or less irregular, having wind- 

 ings similar to those of a corkscrew. The circular 

 galleries in any event have opening from them a 

 number of shorter brood chambers or grooves in which 

 the young are reared. 



This species, like other timber beetles, feeds on 

 ambrosia, a fungus grown in the galleries. Mr Hub- '''f^f ^f^"l 

 bard states that this fungus consists of a confused mass |'^^'^''''=''"'^y 

 of rather large conidia heaped together like fish roe. ^^J^, 

 He states that the cells lose some of their spheric shape by pressure. The 

 general form and structure of this fungus is illustrated at figure 8. 



Hubbard, U. S. Dep't 

 Agric. Div. Ent. Bui. 7, n. s. 



