30 THE ENTOMOLOGIST. 
army of working entomologists as Britain, where probably more 
insects are bred from their earlier states than in all the rest of 
Kurope; under these circumstances the various parasites (especially 
of Lepidoptera) should be well known, but such is not the case. 
Had these been preserved, and either sufficiently labelled or 
recorded by short notes in these pages, the materials at the 
disposal of British hymenopterists would have certainly developed 
an English authority and English memoirs on this interesting 
group; but this we lack. As it is, and as Mr. Marshall has 
remarked, “‘ progress in Ichneumonology requires a large staff of 
workers, and a division of labour ;” thus either the student of the 
Hymenoptera pupivora must be a first-rate general entomologist, 
or else co-operation must exist, so that the preyer and the 
' preyed upon may be correctly determined. Erroneous information 
is worse than useless. Let us, therefore, appeal to the students 
of other orders to attempt to preserve their bred parasites, which 
we hope will not be difficult with the following instructions. The - 
knowledge of the internal parasites should surely form part of the 
life-histories of the various species they affect, and in the case of 
injurious insects their recognition and preservation is of real 
practical value. 
Since it is extremely difficult to identify Ichneumons, whose 
specific characteristics are often very minute or obscure, unless 
some care has been taken in their killing and setting, the following 
hints as to the best methods to pursue are entered into rather 
fully. First, as regards killing, there is nothing equal to the 
fumes of burning sulphur; this permanently fixes the red and 
yellow with which so many species are marked. Cyanide of 
potassium changes these colours, more especially the yellows, 
which it turns into a fine red, and consequently spoils the speci- 
mens. This, as well as chloroform, also renders them so rigid 
that it is with difficulty that the limbs can be displayed. If the » 
insects are killed with sulphur and put into a zine box, with 
a little damp sand or a piece of blotting-paper moistened with 
water to which a drop or two of carbolic acid has been added (of 
course the insects are not to be laid on the moisture, but put in a 
wide-mouth bottle or other convenient receptacle), and left for 
two or three days, they will be in splendid condition for setting ; 
they may even be kept there for a week, provided they be kept 
cool and not allowed to dry. ‘There are two methods of mounting, 
