﻿ECONOMY OF RETINIA RESINELLA. 77 



centre of the nodule, thence proceeding to the base of the young 

 shoot, which is completely hollowed out, and entering the 

 nodule, which is divided into an inner and an outer chamber, at 

 the upper end of the latter, the inner apparently being reserved 

 for pupation. The order of procedure in the formation of these 

 workings would appear to be as follows : — The young larva upon 

 leaving the egg eats through the bark of a twig near the 

 extremity of the old wood, and taking a course in the direction 

 of growth, keeping always on the same side, soon reaches the 

 young growing shoot, upon the soft wood of which it feeds, 

 probably consuming it during the summer of its first year. It 

 now becomes necessary that it should provide for passing the 

 winter, and having weakened the terminal shoot by reducing it 

 to a mere shell at its base, it is desirable that it should provide 

 a more substantial habitation in which to weather the storm ; it 

 is probably at this time that the bark is again pierced, but on the 

 opposite side to that by which the larva entered, and by a larger 

 hole, through which the sap would flow readily, and, congealing as 

 it reaches the air, at once begin to form a resinous mass, which 

 by its own weight, would spread in the direction of the trunk of 

 the tree, the larva as it does so following its movement, and, by 

 removing the bark as it becomes covered, increase the flow 

 of the resinous juices until the nodule has attained a sufficient 

 size ; being hollowed out the meanwhile into the chambers 

 above referred to, and the domicile completed in which the larva 

 is to spend the remainder of its existence. 



It was after having attained this stage that the larvae under 

 notice were first observed in the early days of May, 1888 ; they 

 were still small, and showed little signs of growth until the end 

 of that month ; but from this time they grew rapidly, and by the 

 end of June had the appearance of being full fed, in which con- 

 dition they remained until the spring of 1889, the pupal stage 

 being reached by the 20th April, and the imagines emerged 

 between 25th May and 3rd June. During the time that the larva 

 is in the nodule, it appears to reside in the outer of the two 

 chambers, and to gain what sustenance it requires from the 

 juices that ooze into its apartment from the tree. 



Thus the time from the finding of the larvae to the appearance 

 of the imagines was some thirteen months, and it is evident that 

 the larvae when first noted, had already been feeding for some 

 considerable time, and had indeed completed the earlier stages of 

 their existence ; there appears, therefore, to be no doubt that 

 this species does occupy a period of two years in completing its 

 metamorphoses. 



Wellfiuld, Lingards Road, Lewisham, February, 1890. 



