2 MISC. PUBLICATION 417, U. S. DEPT. OF AGRICULTURE 
felled trees in situations where the bark is particularly moist. Some 
species show a decided preference for moist bark in which the sap 
has already begun to ferment. 
Various species of the genus are attracted in great numbers to 
sawmills and to piled green lumber. Here they may be taken, not 
only in flight, but on the underside of freshly sawn boards and slabs, 
where they feed on the inner bark, in which they often attempt to 
breed. Newly emerged adults often feed upon the tender bark of 
young pines and spruces, and where a heavy beetle populaticn occurs 
near a forest nursery or young plantation many trees may be killed 
by beetles girdling the bark or actually severing the stem at or below 
the root collar. In larger trees they are often found in roots several 
inches below the soil surface. 
Taxonomically Hylastes presents many interesting problems. 
Some species exhibit a surprising degree of variation. In a number 
of the most abundant and widely distributed species, porculus, for 
example, this has led to the production of several synonyms. More- 
over, in long series of little-known forms it is sometimes difficult to 
decide whether one is dealing with a single variable species or with 
several species. 
SYNONYMY OF HYLASTES ERICHSON 
Hylastes Erichson, 1836, Arch. f. Naturgesch. 2: 47; Westwood, 1840, Introduc- 
tion to Modern Classification of Insects, v. 2, p. 39; Perris, 1856, Soc. Ent. 
de France Ann. (8) 4: 228; Thomson, 1859, Skandinaviens Coleoptera 1: 
146 (Bostrichus ater Payk. designated as genotype) ; Hichhoff, 1864, Berlin. 
Ent. Ztschr. 8: 23, 44, 46; Leconte, 1868, Amer. Ent. Soc. Trans. 2: 168, 
174; Chapuis, 1869, Synop. Scolyt., p. 16 (extract from Soc. Roy. des Sci. 
de Liége Mém. (2) 3: 224, 1873) ; Leconte, 1876, Amer. Phil. Soc. Proc. 15: 
387; Hichhoff, 1881, Europ. Borkenkifer, pp. 35, 76; Bedel, 1888, Faune des 
Coléopt. Bassin de la Seine 6: 388 (as synonym of Tomicus Latr.) ; Reitter, 
1895, Naturf. Ver. in Briinn, Verhandl. (1884) 33: 59; Blandford, 1896, 
Biol. Cent. Amer. Insecta-Coleopt. 4 (6): 148; Barbey, 1901, Scolyt. de 
l'Europe Cent., p. 41; Hopkins, 1915, U. S. Natl. Mus. Proc. 48: 122; Hopkins, 
1915, U. S. Bur. Ent. Tech. Ser. Bul. 17: 221; Swaine, 1918, Canada Dept. 
Agr. Ent. Branch Bul. 14 (2): 77 (doubtfully referred to Tomicus Latr.) ; 
Munro, 1926, [Gt. Brit.] Forestry Comn. Bul. 8: 41, 54; Bruck, 1936, South. 
Calif. Acad. Sci. Bul. 35: 46. 
Tomicus Latreille, 1802, Hist. Nat. Crustacés et Insectes 3: 208; Bedel, 1888, 
Faune des Coléopt. Bassin de la Seine 6: 388; Swaine, 1909, N. Y. State Mus. 
Bul. 184: 144; Swaine, 1918, Canada Dept. Agr. Ent. Branch Bul. 14 (2): 77. 
Hylurgus WLatreille, 1807, Genera Crustaceorum et Insectorum 2: 274; Zimmer- 
mann, 1868, Amer. Ent. Soc. Trans. 2: 149; Leconte, 1868, Amer. Ent. Soe. 
Trans. 2: 174 (as synonym of Hylastes Er.). 
DESCRIPTION OF THE GENUS 
Body form cylindrical, ranging from moderately stout to slender; color 
reddish brown, piceous, or black; subopaque to shining; sculpture moderate 
to strong; pubescence usually scanty and inconspicuous. Head with a short, 
stout beak, approaching certain of the Cossoninae in this respect, grooved at 
each side for reception of antennal scape; antennal funicle 7-jointed, pedicel 
little larger than others, club rather small, oval, not flattened, distinctly 
annulated, with first segment comprising about half of club; eyes rather short 
ovate, the inner line entire. Pronotum longer than wide, narrower than elytra, 
moderately to very coarsely punctured, with surface between punctures varying 
from smooth and shining to opaque, occasionally with granules. Elytra wyih | 
bases rather weakly arcuate, elevated, irregularly serrate; striae variably 
impressed, punctures moderate to coarse, often wider than interspaces. 
