PREFACE. 



I REGRET that from chang^e of circumsianccs the publication of ' Aid " 

 must, at least for the present, be discontinued. In my second volume I 

 have as far as possible adhered to my original design. After part 15, 

 however, acting" on the sug-g-estion of some of my subscribers, I 

 introduced the system of figuring more than one species on each plate, 

 by which means I was able to give representations of twenty-five species 

 for a subscription up till that time paid for sixteen figures. 



Although this plan certainly has its advantages, it increased very 

 g-reatly my labours as editor, a circumstance which would not in itself 

 have prevented me carrying" on the work, but which, when combined with 

 others, has had considerable weight in deciding me to discontinue the 

 publication. 



I originally undertook the work on account of the great need which I 

 felt of good figures. Thousands of species are annually described, but 

 few descriptions are accompanied even by a wood-cut, and the difficulty 

 of determining insects without such help is only too well known. I felt 

 therefore that I could scarcely do the cause of sybtematic entomology 

 greater service than by publishing- a work of this kind, and it is with the 

 greatest reluctance that I discontinue it. That I do not believe species 

 can (except in a few cases) be determined with certainty from a figure 



