Investigations into the insects injurious to the spruce 
and pine cones. 
(Swedish text pp. 1140—1204). 
BY IvAR TRÄGÅRDH. 
The purpose of the investigations was to ascertain what were the insect pests 
of spruce and pine cones, to study their distribution, biology and economic 
importance, their parasites, the distribution and importance of these, further 
to study the influence of the attack on the germinating power of the seeds, 
the possibility of drawing conclusions regarding the quality of the cones from 
their exterior appearance, and other questions. 
From a practical point of view, it is possible to distinguish between three 
different kinds of insect pests of the cones: one causes the cones to drop to 
the ground prematurely and can, as a consequence, only be studied by col- 
lecting the cones of certain trees at regular intervals; the second group does 
not cause the cones to drop to the ground but leaves them for hibernation 
purposes and must therefore be studied during the summer and autumn; the 
third, on the other hand, hibernates in the cones and can be studied on ma- 
terial collected during the timber-cutting in the winter. 
The last group is obviously the easiest to study and for this reason the 
investigations began with the fauna of the spruce-tree cones during the winter. 
Material consisting of 200 cones from each locality was secured with the aid 
of the rangers and the Royal foresters from some 70 localities (see map fig. 2) 
and kept in breeding-cases of the American type ifig. I). 
The identification of those Chalceididae which it was not possible to identify 
with the aid of RATZEBURG'S work has been made by Dr. RuscHKA of Vienna, 
Professor J. KIEFFER, Bitsch, Germany, has verified the identification of the 
gall-midge; and Dr. A. ROMAN has identified the Ichneumonidae. 
Review of our present knowledge of the spruce:tree cones in 
Sweden. LINNAUS (1758) only knew Laspeyresia strobilella, DE GEER (1771), 
on the other hand, bred from the cones all the three lepidoptera hitherto 
known as pests of the spruce-tree cones in Sweden, viz., Eupilhecia abietaria, 
Phycis abietella and Laspeyresia strobilella. DAHLBOM (1837) does not mention 
any insect pests of the cones at all. HOLMGREN (1867) described briefly the 
injury done by ÅLaspeyresia strobilella and Anobium abietinum, and mentions 
other more rare species of the latter genus as pests of the cones. WAHLGREN 
(1893) published some new observations of the spruce-tree cone insects. He 
ascertained that 67.6 & of perfectly healthy-looking cones were attacked by 
Laspeyresia strobilella, and that of those visibly injured 65.7 22 were damaged, 
which signifies that no conclusions can be drawn from the external appearance 
of the cones. WAHLGREN found also in the cones white cocoons, containing 
yellow larvae, which he believed to be parasites of the larvae of the cone moth. 
