152 [July, 



blackened and spoilt. Bright or yellow-coloured species, such as 

 Syrpliidce, are especially liable to change. Under these circumstances 

 I thought that I would look out for some other salt which would give 

 off poisonous fumes without being deliquescent, and it struck me 

 that perhaps benzoline (the smell of which is destructive to mites), 

 might answer the purpose if the fumes were sufficiently concentrated. 

 Upon making a trial I find that it answers admirably ; some of the 

 salt crushed or in small crystals must be placed at the bottom of a 

 phial or small wide mouthed bottle, then covered with a little cotton 

 wool and wedged down and fixed with some paper. The quantity of 

 benzoline must not be very small, for the fumes are scarcely so deadly 

 as those of cyanide, and require to be strong. I find that a bottle 

 so prepared will kill flies in a few minutes, and the specimens take 

 no harm if they remain in the bottle until the next day unless there 

 are a large number of them together. 



There seems to be no deliquescence of the benzoline, as the salt 

 remains hard and dry, and the insides of the bottle do not get damp, 

 though closely corked up ; the evaporation also goes on very slowh^ 

 so that the bottles will last a very long time without replenishing. I 

 do not think that Mr. Saunders' plan of having a tube through the 

 cork would answer in the use of benzoline, as it is necessary to keep 

 the bottle tightly corked. 



Bradford: June Wih, 1897. 



ODONATA COLLECTED BY THE EEV. A. E. EATON IN ALGERIA: 



WITH ANNOTATIONS. 



BY ROBERT McLACHLAN, F.R.S., &c. 



Since the end of 1892 my friend Mr. Eaton has passed the greater 

 part of his time in Algeria, and has made extensive collections, which 

 he has most liberally handed over to specialists. The Neuroptera have 

 come to me, and I herewith give details of what he has found among 

 the Oclonata. He did not visit the Province of Oran, and paid very 

 little attention to Dragon-flies while in the Province of Algiers, so 

 that the greater part come from the eastern Province of Constantino. 

 He secured 31 species (or about two-thirds of those recorded from 

 the country), amongst which three, viz., Onychogomphiis Genet (in two 

 races, very interesting), jMschna rufescens and Enallagma cyathigerum, 

 are additions to the Fauna. I am also able to describe the hitherto 

 unknown $ of Onychogomphus Costw. 



In the course of working out the materials certain observations, 

 critical and otherwise, have occurred to me, and have been incorporated. 



