252 THi; CANADIAN ENTOMOLOGIST. 



depression pale golden pollinose without any carina. Antennae reaching lowest 

 fourth of face, all three segments black ; the third segment about one and one- 

 fourth times as long as the second. Arista thickened on basal half, the pen- 

 ultimate segment scarcely longer than broad. Width of front at narrowest point 

 equal to abovit three-fourths the length of the second antennal segment ; the 

 front silvery pollinose ; frontal vitta reddish brown, the narrowest width equal 

 to about one-half the width of front at vertex. No orbital bristles, the pro- 

 clinate ocellar bristles fairly well developed; the single row of frontal 

 bristles descending to about the middle of the second antennal segment. 



Thorax subshinnig, black, covered with gray pollen, scutellum gray pol- 

 linose on a black groimd and showing no red coloration even at the extreme 

 tip. Typically three sternopleural bristles and three pairs of dorsocentrals ; 

 scutellum with three strong pairs of marginal macrochaetae, with an apical 

 cruciate weaker pair and without any discals. Legs black, the middle tibiae 

 with two or more bristles on the front side near the middle, the hind tibiae with- 

 out a comb-like row of bristles on the outer side. Wings hyaline ; R^^- (third 

 vein) with a group of two to five hairs both above and below at the junction of 

 R2+3 ; the bend of M^+o destitute of an appendage. Tegulae white. 



Abdomen subshining; ver)- lightly silvery pollinose on a black ground. 

 Discal and marginal macrochaetae present on the second, third and fourth ab- 

 dominal segments. The hind margin of the third tergum very strongly arcuate ; 

 the fifth tergum readily marked off from the sixth at the lateral part but medial- 

 ly indistinguishable from it. The lateral width of the fifth tergum equal to 

 about one-third the lateral width of the fourth abdominal segment ; the sixth 

 and seventh abdominal segments forming the somewhat distended genital seg- 

 ments. 



Genitalia black; differing from all other known nearctic species in having 

 an exceedingly long keel-like portion at the base of the inner forceps (named 

 on account of this unusually long keel). The basal part of the outer forceps 

 covered over by a broad, leaf-like portion. 



The horseshoe-shaped indenture of the last sternite extending slightly 

 more than half the distance to the base of the blade. 



Described from four males collected by Mr. E. C. Van Dyke at Lake 

 Tahoe, California on September 20th. 



Type and one paratype in the Cal. Acad. Sci. One paratype in the Can- 

 rmadian National Collection. Ottawa. One paratype in the U. S. N. M. 



(To De Contiimed. t 



A REVIEW OF THE GENUS MONOCHAMUS SERV. 

 (CERAMBYCIDAE, COLEOPTERA) 



BY RALPH HOPPING, 



Entomological Branch, Depaa-tment of Agriculture. Ottawa. 



A study of long series of the different species of this genus has made 



it evident that a few changes in the synonomy are necessary. The writer's 



interpretation of the North American species is expressed in the accompanying 



key. 



