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inary attack, and become as familiar as possible with its life history and 
habits, as well as the life history and habits of other species cooperating 
with it, and also study other causes which might contribute to or oppose 
the progress of their destructive work. 
In the consideration of preventive measures against invasions of 
Scolytids, we must study the habits of the different species of the 
family in order to ascertain which of them are capable of causing dis- 
eased conditions of trees, or through increased numbers, their death. 
During an investigation of serious trouble caused by these insects 
in our State I have given especial attention to these subjects. After 
discovering the species to blame for the primary attack, and its prin- 
cipal aids in continuing the devastations, methods of checking the 
increase of the destructive kinds and protecting forests of healthy 
timber from their invasions were considered. 
I was convinced from the first that no artificial remedy, such as 
cutting and burning the infested trees, the removal of the bark from 
the trunks, etc., could be successfully applied in our West Virginia 
forests. Therefore, my attention was turned toward the study of the 
parasitic and predaceous enemies of Scolytids, with a view of ascertain- 
ing the most desirable kinds with which to conduct experiments, in 
utilizing them as a means of checking the increase of the destructive 
species. 
An enemy of Scolytids was desired which would not have to depend 
on one or two species for its existence, but could readily adapt itself to 
different species and to varying conditions. 
I found that while Scolytid bark beetles have numerous parasitic 
Chalcidid, and Braconid enemies, few, if any of them, in my opinion, can 
be relied upon as introduced enemies to suppress or prevent an invasion 
of these beetles. I found, however, among their predaceous enemies, 
that the habits of certain species of the coleopterous family Cleridge 
were such, if these beetles occurred, or could be introduced in suf- 
ficient numbers in the infested forests this would certainly have the 
desired effect. 
In my search for literature regarding native and European Clerids I 
found, in a report upon forestry, by F. B. Hough, 1882 (p. 264), as 
copied from a special publication of the French Forestry Administra, 
in connection with the Universal Exposition at Paris, that a Euro- 
pean species, Tillus formicariusj was mentioned as being a "foe of Bos- 
trichus typogra/phus that pursued them without mercy" during an 
invasion of these bark beetles in the forest of Abies excelsa in the Jura 
mountains, from 1868 to 1872. This led me to make further inquiries 
in regard to this and other European enemies of Scolytids and on 
October 13, 1891, 1 wrote to my correspondent, Oberfoerster W. Eichhoff, 
of Strasburg, Germany, asking him to send me some pinned specimens 
of insects known to be special enemies of European Scolytids. At the 
same time I indicated to him my desire to introduce live examples of 
