CXLVI I. TRÄGÅRDH. 
Very likely this method may also be applied in the investigations of other 
complicated bioccenoses, when direct observations regarding the relationship 
of the insects to each other are difficult to make, as for instance large galls, 
which are often inhabited by many different species, and tree-trunks. Itis 
therefore desirable that other entomologists should employ and give the me- 
thod a trial. 
