8 Introduction 



from the type, and they will bear numbers 2/10, 3/10, etc. If all 

 the specimens exactly agree they will be numbered 1/10. Any speci- 

 men can be indicated in the original description by its fractional 

 number. 



6.— STUDIES ON THE GENITAL AEMATUEE. 



Mr. Joicey has equipped a small laboratory in connection with the 

 Museum for the purpose of carrying out work on the genitalia. This 

 is in charge of Mr G. L. Birbel, and all dissections and drawings are 

 by him unless otherwise stated. The morphological differences are also 

 worked out by Mr. Birbel. 



A process has been developed whereby dissections can be made 

 without the abdomen sustaining any obvious mutilation. A full account 

 of the technique will be given in a future number of the journal. 



It is not possible to carry out dissections of all described forms, as 

 time would not permit, but the new technique enables us to dissect 

 specimens which may otherwise not become available. 



The nomenclature employed in describing the organs is the one 

 given by Dr. J. McDunnough, the Canadian Entomologist, vol. xliii, 

 June, 1911. 



The terms anterior, posterior, dorsal, and ventral, are used in relation 

 to the whole of the organs, e.g., where the valve is connected with the 

 sternite, this is the anterior end. 



7.— THE INCORPORATION OF NEW MATERIAL. 



If a collection of insects is built up for scientific study, some care 

 must be taken in the acquisition of material. We endeavour to keep 

 as near as possible to the following plan in making accessions : — 



(1) Forms not represented in the collection. 



(2) Material from a zoological area which is as yet unrepresented 

 in the collection. 



(3) Type specimens of any kind. 



(4) Material provided with proper data, and serving to replace 

 specimens not so provided. 



(5) Forms already in the collection but which are subject to 

 variability. 



(6) Forms already in the collection but which may be replaced by 

 better specimens from the same localities. 



