REPORT OF THE SICIETY 107 



extensively in the larger boughs, often at the intersections with the main trunk, 

 weakening these to such an extent that they readily crack and break down 

 when swayed bj^ a strong wind. 



The following statement shows the number of scars per branch, found 

 on one tree: 



18 



Total No. of Scars- — 47 

 Average per Branch- — 3.6 



29 



The majority of these wounds were healed over and contained no larvae; 

 judging from the rough chiselled incisions made by woodpeckers it is most 

 likely the birds secured some of the grubs. 



&i\k &}nnning.- — Under natural conditions the larva spins its silk through- 

 out the entire boring operations from the time of emergence from the egg until 

 the final stage of pupation. 



A young larva placed in a glass vial spun white, cobwebby patches of silk 

 over the surface, almost excluding itself from sight. 



The silk is mixed well with the frass in the tunnel, the fine threads holding 

 this material together in clots and loose masses; especially is this noticeable 

 in the pellet and sawdust varieties of castings. 



Boring Frass. — Several kinds of boring material are turned out by the 

 larva as it works its way from the outer bark to the wood within. By the 

 character of the frass it expels, the progress or location of the larva within the 

 trunk can be determined with some degree of accuracy. These castings may be 

 described as follows : 



1. Fine brown dust grains held loosely by invisible threads, thrown out 

 by the very young larva when starting in a crevice. 



2. A da.-k coloured, sappy material produced by the young larva within 

 the outermost layers of the bark, during the early stages of excavation. 



3. A airty mixture of dark coloured and mushy-pulp matter, indicating 

 the larva is entering or working in the sapwood. 



4. Dry, white sawdust borings at [he tunnel's entrance which have be- 

 come mixed with coarse, dark pellets and droppings held together loosely by 

 fine threads. This is a fair indication that the larva is excavating within the 

 heart of the tree. 



PUPA 



The pupa is dark reddish brown or mahogany coloured. It is well rounded 

 and shining. The eyes, antennae, legs and wings are well seen beneath their 

 thin chitinous coverings, the sutures being clearly defined. The female case 

 averages 45.omm. in length and 10.8 mm. in width; and the male 24.5 mm. long 

 and 6.0 mm, wide. There is a decided curve ventrally at the posterior end of 



