166 AUSTRALIAN WOODBORING COSSIDAE 



incorporate segment 3 also, and in C )3sinae 3 is so incorporated, 

 but Cossidae — both Zeuzerinae and Cossinae — retain a character 

 relatively more ancient than that of Hepialidae, that is, the 

 freeing by disseverance of the appendages from the abdominal 



segnients on dehiscence. 



Zeuzerinae — Endoxyla.* 



Description of larvae. — The dorsal horns of anal segment 

 may prove a good (fencric character. The arrangement of scutel- 

 lar spicules is probably a good apecific character. 



E. bomlm-nlii—'' Roths." (Plate VII., Fig. 6.) 



t The larva at an early age feeds beneath a light-coloured 

 silken web, which falls off subsequently when the larva has 

 burrowed into the wood of the tree ; our description is made 

 from a larva 35mm. in length, it has at this stage a very pleas- 

 ing plumage, being ringed alternately red and yellow, it is in 

 appearance quite an elegant aristocratic larva, but with approach- 

 ing maturity loses its remarkable coloration. 



* Derived from endo and xulon. 



t The first intimation of the presence of the larva is readily noted by this 

 freshly-formed web of loose silk arid gnawed pieces of the bark of the tree, 

 upon raising which the caterpillar may be seen, either partly buried in the 

 bark and young wood or quite entered within the small tunnel it has bored. 

 Later on the bark begins to grow over the opening made into the tree, the 

 web falls off or is blown away by the wind, and a small circular scar is the 

 only indication then left of the insect inside the tree. The larva continues 

 tunnelling towards the centre of the tree, increasing in size, and the boie 

 becoming larger. Having gone as far as the heart of the tree, or nearly so, 

 it cu ves upwards at right angles to its former course for from 6 to 8 inches, 

 and completes the remainder of its existence by feeding upon the constantly 

 forming young wood and sappy matter, sometimes making two or tlu-ee 

 short pseudo-bores at the foot of the perpendicular tunnel, which together 

 form a large chamber within the stem of the tree. Having attained full 

 growth within it prepares for its change and exit as an imago or winged 

 insect by gnawing outwardly with its powerful cutting mandibles, and forms 

 a clean cut round hole often nearly an inch and a-half in diameter upon 

 the outside of the tree. This opening is frequently blocked up by triturated 

 fragments of wood loosely spun together with silk. The next process is the 

 retreat of the insect to the perpendicular tunnel, where it first forms a most 

 singular network of a very viscous substance from 1^ inch to 2 inches in 

 depth, which when first formed is a pure glistening white, but becomes 

 yellow with age. On this it forms its operculum of finely triturated wood 

 closely felted together with silk and saliva. Having completed all its 

 arrangements the larva, now head downwards, and quite filling up the 

 chamber-room left, turns to a pupa (chrysalis), and in the course of a month 

 or six weeks, occasionally longer, the imago emerges in the manner usual to 

 insects of this group. 



