Notes on Reproductive Organs of the Pine Weevil. 161 
XXI.—Notes on the Reproductive Organs of the Pine Weevil 
(Hylobius abietis). By James W. Munro, B.Sc., Natural History 
Department, University of Aberdeen. 
(Read 15th December 1913. MS. received 6th January 1914.) 
THE reproductive organs of an insect have a three-fold interest: they are 
interesting to the anatomist; to the systematist they afford valuable 
secondary characters for the identification of species; the worker in economic 
entomology finds them of the first importance as a guide to the main facts in 
an insect’s life-history. 
The following description forms the groundwork of a research on the life- 
history of the pine weevil, one of the worst insect enemies of the forester 
in this country. With a large number of insects, and especially the moths, 
the life-history may be said to end almost as soon as the insect reaches the 
imago stage. With the pine weevil, on the other hand, the life-history is 
most interesting after the insect is adult. 
In the larval stage Hylobius abietis is harmless. It is when it appears as 
the adult weevil that it becomes a serious danger to the forester. It then 
attacks young or newly planted conifers, and even hardwoods, gnawing the 
tender bark of the main stem and branches, and so killing the young plants. 
This damage is termed by the Germans the “reifungs frass,” or ripening frass, 
and the name is singularly appropriate. : 
The following description of the reproductive organs of H. abietis is the 
result of work carried out in the Royal Forest Academy of Tharandt in 
Saxony, under the supervision of Dr Karl Escherich, Professor of Zoology in 
that Institute. Iam greatly indebted to him for his advice and encourage- 
ment while engaged on it, and also to his temporary assistant, Dr Prell, of 
Marburg University, from whom I received valuable hints on the dissection 
of specimens and the making of preparations and sketches from them. 
These notes are based largely on the examination of weevils found in 
the neighbourhood of Tharandt. I collected these as I required them from 
recently felled areas of Scots pine throughout the months of June and July of 
this year (1913). For the description of the genitalia I have used material 
collected in the neighbourhood of Schénefeld, in Saxony; and for revision 
work and biological observations, weevils collected in the neighbourhood of 
Aberdeen, Scotland. 
_ The beetles for dissection were killed by chloroform, and examined 
immediately afterwards The elytra and wings were first removed, and an 
incision made along each side from the anus anteriorly, and the terga removed. 
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