The Genus Hylastes, Er. 123 
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—‘“‘ The genus Hylastes, Er., and its Importance in Forested” 3a an nstiz, 
Study in Scolytid eimietute and Biology.” By James W Munro, 
B.Se. (Agr.), B.Sc. (For.). Communicated by William Evans, BS. BE Pp 
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(With Plates and Text-Figures.) Pooe 
(Received 18th December 1916. Read 18th December 1916.) 
In the British literature on the Scolytide or Bark Beetles little attention has 
been paid to the genus Hylastes, and even from economic workers in the 
group the genus has received only scanty consideration. 
The genns Hylastes, Er., comprises five British species, of which three are 
of considerable interest to the forester, namely, Hylastes ater, Pk., H. palliatus, 
Gyll., and H. cunicularius, Er. The remaining species, H. opacus, Er., and 
H. angustatus, Herbst, are sufficiently uncommon to be considered rare by 
collectors of the Coleoptera. 
It is the object of this paper to describe the general structure, life-history, 
and habits of the various species of Hylastes, and especially to estimate their 
economic importance in our woodlands. The writer has practical experience 
of only three of the five species, and this paper is accordingly confined to these 
three, namely, H. ater, Pk., H. cunicularius, Er., and H. palliatus, Gyll. In 
the case of H. ater and H. palliatus systematic observations on the life- 
history and habits have been made both in the field and in the laboratory. 
In the case of H. cunicularius no laboratory observations were made, and 
the field observations were unfortunately made at somewhat irregular 
intervals. The latter, however, are of sufficient interest to justify some 
account of them being given here. 
MATERIAL. 
Three sets of material have been made use of in the study of Hylastes. 
(a2) Material used for the comparison of the various species and the 
description of the structure of H. ater. 
(b) Material used in the laboratory observations and confined to 
the two species H. ater and H. palliatus. 
(c) Material studied in the field. 
Material for Comparison of the Species. 
Adults and larve of H. ater and H. palliatus were obtained from prattically 
all the eastern counties of Scotland during 1914-16. HZ. cwnicularius material, 
VOL. XX. a L 
