A CAUTION TO ENTOMOLOGISTS. 3.17 



Sometimes two, or even more, of the galls will be made so 

 close together that they coalesce to a greater or smaller de- 

 gree. I possess one rather remarkable instance of this fusion. 

 Contrary to the general practice, the instinct of the enclosed 

 insect misled it. After the pupa has changed into the perfect 

 state, the Cynips gnaws its way through the substance of the 

 gall, and so gains the outer air. The distance to be traversed 

 is about half an inch, and the insect has quite enough strength 

 to accomplish the task. But, in the instance of wliich I speak, 

 one of the Gall-flies had mistaken its way, and, instead of 

 directing itself to the point which would lead it most directly 

 into the open air, unfortunately took exactly the opposite direc- 

 tion, and hit upon the very spot where the galls were joined 

 after the fashion of the Siamese twins. Consequently, instead 

 of having to gnaw its way through a wall barely half an inch 

 in thickness, it had to traverse an inch and a half before it 

 could reach the air. Very naturally, its strength was ex- 

 hausted before it could perform such a task, and I found it 

 lying dead on the spot where the galls were joined. 



To me, one most interesting point was to observe tlie 

 economy of Nature even in so small an insect as a Grall-fly. 

 Normally it has to bite its way through half an inch of material, 

 and it has strength for that purpose. But it has not more 

 than sufficient strength, and so it happened that the insect in 

 question, after traversing its allotted half inch, had no strength 

 to proceed further, and so died on the scene of its uncompleted 

 labours. 



An insect so plentiful, so conspicuous, and so sluggish 

 might be supposed to suffer much from birds. It has, how- 

 ever, been well observed that this species has, when handled, 

 a very disagreeable odour, and that therefore the birds may 

 reject it, as is known to be the case with many other insects. 



It is impossible, with the limited space at our command, to 

 do more than give this brief sketch of the life of a Grall-fiy. 

 There are very many other species, some of which are exceed- 

 ingly beautiful and others comparatively dull. Breeding them 

 from the gall is a very interesting pursuit, but I must warn 

 the novice in this art that, although he may hatch a number 

 of Hymenoptera from galls, it does not by any means follow 



