400 PROCEEDINGS OF THE NATIONAL MUSEUM VoL. 92 
Generic description—Body stout, oval, strongly convex, orna- 
mented with hairs and scales; frons convex, often weakly impressed 
in female, concave or strongly impressed in male; eyes strongly 
emarginate; antenna with funicle 5-segmented, with outer segments 
wider, club elongate, compressed, with three more or less oblique 
sutures; pronotum wider than long, posterior outline bisinuate; 
prosternum moderately short; fore coxae moderately widely sepa- 
rated; elytra with anterior margins arcuate, serrate; striae distinctly, 
often strongly, impressed, always narrower (often much narrower) 
than interspaces; declivity with alternate interspaces, especially in 
male, more strongly asperate or serrate, second interspace often devoid 
of serrations. 
Genotype—Hylesinus thujae Perris from France, designated by 
Hopkins, 1914. 
KEY TO NORTH AMERICAN SPECIES OF PHLOEOSINUS CHAPUIS 
1. Frontal rectangle* of male nearly or quite as long as wide; that 
of female 0.8 to 0.9 as long as wide; epistomal lobe narrow, 
moderately long; mesosternum precipitous and protuberant be- 
tween coxae; elytral declivity with all interspaces convex and 
subequally asperate in both sexes; breeding in pines or spruces___-______ 2 
Frontal rectangle of male from 0.6 to 0.8 as long as wide, that” 
of female wider; epistomal lobe small or nearly absent; 
mesosternum varying from precipitous to flat between coxae, 
never protuberant; elytral declivity with second interspaces 
either flat or much less convex than others, asperities absent 
in male at least; breeding in taxodiine or cupressine trees____________ 4 
2. Width of frontal concavity of male less than half distance be- 
tween eyes; pronotal disk and sides distinctly granulate- 
punctate ; breeding in pines; Manitoba and Michigan__ pini Swaine (p. 407) 
Width of frontal concavity of male half or more distance 
between eyes; pronotal disk punctate, sides subgranulate- 
punctate scbreeding ain |S Prides ee ee eee ee 3 
3. Pronotum in female slightly longer than wide, wider than long 
in male; Quebec, in white spruce___________-_____ piceae Swaine (p. 408) 
Pronotum distinctly wider than long in both sexes; Alaska, in 
White spruces a= = te ae A eee alaskanus, new species (p. 409) 
4. Second interspace on elytral declivity narrower than (or at most 
subequal to) first or third, never serrate in either sex; 
elytral vestiture either abundant or nearly absent______....______-____ 5 
Second interspace on elytral declivity as wide as first or third, 
not serrate in males, often serrate in females, elytral vestiture 
rather abundant. Jctiris _ feb. ise. Cae oe ee 31 
5. Usually small species, averaging slightly more or less than 2.0 
mm. long (except keeni) ; mesosternum precipitous or steeply 
oblique between coxae; vestiture of pronotum and elytra 
usually rather abundant and distinet_________________- OFS LE IS 6 
1The width of the frontal rectangle is the distance between the inner margins of the 
eyes. Its length is the distance between a line connecting the upper margins of the eyes 
and a line parallel to it and touching the lower edge of the epistomal process. 
