﻿76 THE ENTOMOLOGIST. 



special attention. It is surprising to me that galls and their 

 inhabitants are not more a subject of study among entomo- 

 logists.* 

 West Cliff, Custer Co., Colorado, January 23, 1890. 



NOTES on the ECONOMY of RETINIA RESINELLA, Linn. 

 By E. Adkin, F.E.S. 



In the spring of 1888, I heard from Mr. Salvage, who was 

 then collecting in the neighbourhood of Forres, that a number 

 of the twigs of the Scotch fir (Pinus sylvestris, L.) had attached 

 to them nodular masses of resinous matter containing larvae, 

 which he believed to be those of Retinia resinella, and I sub- 

 sequently received some of the twigs from him. These I placed 

 in sand, kept moistened so as to prevent the twigs becoming 

 unnaturally dry, and allowed them to remain out of doors until 

 the imagines emerged ; in the interim observations were made, 

 with a view, more especially, of ascertaining any facts that 

 might have a bearing upon the opinion that had been expressed, 

 that the larva of this species occupied a period approaching two 

 years in feeding up. 



Examining the twigs externally when received, it was evident 

 that the resinous nodules were invariably fixed to wood of the 

 previous year's growth ; that what should have been the leading 

 shoot of the then present year was much dwarfed, and in some 

 cases represented by little more than a bud, giving the impres- 

 sion that it had been mined at some anterior period. This 

 at once suggested an examination of the interior, but as it would 

 have been necessary to open several twigs to gain any satisfactory 

 information in this direction, and as such a proceeding was 

 calculated to kill the larvaa, it was postponed until such time as 

 the moths should come forth ; only a sufficient number of the 

 nodules being opened from time to time to ascertain the condition 

 of their tenants. In due course the desired conditions were 

 fulfilled, and it was then found that the most satisfactory 

 method of arriving at the object in view was by cutting longitu- 

 dinally through the twig and nodule together, the fibre of the 

 former and the semi-crystalline substance of the latter yielding 

 readily to the persuasive dissecting knife, and thus exposing to 

 view in section the workings made by the larva throughout its 

 life. These maybe briefly summarised thus : — A narrow gallery 

 under the bark of the twig, on the side opposite to that to which 

 the nodule is attached, commences at a point nearly level with the 



* Note. — I am indebted to Dr. C. V. Eiley and Mr. W. H. Ashmead for identifi- 

 cation of several of the galls mentioned. The new species will be fully described 

 hereafter, 



