﻿1870.] 185 



its crannies, but none were to be seen ; so, knowing that an escape had been im- 

 possible, I carefully began to examine gall after gall, when it soon turned out that 

 several of them were filled with the closely packed cocoons, divided only by walls, 

 composed of frass intermingled with silken threads to keep the fabric together. 

 Deprived of their usual resources, the sagacious creatures had crowded together in 

 some of the most capacious galls, and spinning (against their custom) gregariously, 

 had used their own frass as a substitute for earth. 



The few perfect insects bred from Mr. Kidd's batch appeared 4 — 6 weeks after 

 spinning their cocoons. They liberated themselves in the usual way, by cutting 

 off the top of the cocoons with their mandibles. 



In 1868, I collected a few of these galls near Penge, as late as October the 9th ; 

 the larvse were full-fed about the 16th of the same month, but died in their cocoons. 

 However, it is very likely that the autumnal brood passes the winter in the cocoon 

 as larva, the fly appearing in spring. At the present time, the galls in all stages 

 are plentiful in this neighbourhood. — Albert Muller, South Norwood, S.E., 

 6th September, 1869. 



On the examination of living gall-midges. — The circumstance, that the minute 

 species of Cecidomyia are peculiarly liable to shrivel up, and to change their 

 colours soon after death, particularly if the latter be brought on by artificial and 

 quick means, necessitates their examination whilst alive, as most of the published 

 descriptions, and very properly so, are di'awn up from such specimens. 



But, on the other hand, their great vitality and restlessness present consider- 

 able obstacles to the observer who attempts doing so. 



After several unsuccessful experiments, I have accidentally hit upon a simple 

 plan, which allows one to examine these delicate insects closely, whilst alive, and at 

 the same time renders them immobile, as far as head, antennae, body, halteres, and 

 legs are concerned. 



By exposing them to the scent of " Eau de Cologne " (and I find that anything 

 stronger will not do), and, of course, without wetting them at all, they lose after 

 a few minutes the power of moving their limbs ; the wings alone are lifted up and 

 begin to vibrate rapidly, so much so as to become almost invisible. 



This state lasts about twenty minutes, during which time every other part is 

 stiff and still, the sexual organs being generally much protruded, a matter of no 

 small importance in the separation of closely allied, yet distinct species. 



During this partial collapse of vital action, the midges, possessing still all 

 the fullness of outline and colours of life, may be tnrned over and examined care- 

 fully, and when the sudden stoppage of the alary vibration indicates that the 

 painless end has arrived, the investigation may be terminated by scrutinizing the 

 neuration of the wings, and setting the flies for the collection, in which, however, 

 their shrivelled bodies present, as a rule, anything but a good appearance. — Id. 



Semasia olscurana, a gall inquiline. — There having been some doubt as to the 

 identity of the Tortrix bred by Mr. C. W. Dale from oak-apples, as recorded by him 

 in the November number, p. 146, we requested that gentleman to allow us to examine 

 it, which he obligingly did. It appears to be a small starved example of Semasia 

 obscurana, Steph., a somewhat rare species, generally found among undergrowth 



