578 FAMILY IV. SCOLYTIDJE. 



a rate family, which course is also supported by their more linear 

 form. The anterior tibia? are usually compressed and serrate on 

 the outer margin, sometimes without teeth on the edge but pro- 

 duced at apex into a curved process or inucro (Scoly- 

 tinae) ; the thorax is usually without any side mar- 

 gin, sometimes, however, margined (Scolytiua?) ; the 

 elytra usually have a pronounced declivity at apex, 

 which is sometimes lacking, in which case the abdo- 

 men may ascend obliquely to the apex (Scolytinae). 

 of These differences have caused the Scolytinse also to 

 lytidx, '"show- be set apart either as a tribe or subfamily. The head 

 fourth 8 joint, is never prolonged into a beak, but is often suboblong 

 kfns.) P and prominent (Hylesinini), otherwise globose, 

 deeply immersed in the thorax (Ipini) ; the thorax 

 is sometimes uniformly sculptured (most Hylesinini), sometimes 

 remarkably roughened in front with sharp, backward-pointed 

 spines (Ipini) ; the declivity of the elytra may be unarmed 

 (Hylesinini) or provided with tubercles or spines (many Ipini). 

 The maxillary lobe is usually beset with stout radiating 

 spines, but in those genera which bore into solid timber ( Xijlo- 

 terus, Xylebortis and the Corthylini) these are replaced by long 

 bristles. The basal margin of the elytra is elevated, toothed or 

 tuberculate in some genera of Hylesinini; the third interval is 

 elevated at apex in others (Carphobonis) ; the sculpture of the 

 thorax is often longitudinally strigose, as in Cucxiiuifi, or with a 

 few distant acute tubercles in front of middle ((.'ri/)tli<ilitx\ ; the 

 body is sometimes clothed with small scales and stout erect 

 bristles in rows (CJiranicsus). 



The sexes do not usually present great differences, though 

 the male head is bispinose in Phla'Otrilmx. bituberculate in Car- 

 />Iiol><>nix, but in the Xyleboriui, this condition is reversed, the 

 male differing greatly in form of body, by horns or excavations 

 on thorax, or by marked flattening of the surface; such males are 

 however rare in collections, as they may not leave the heart of the 

 tree in which they were born.* 



The principal works on our species of Scolytid;e are Zimmer- 

 man and LeConte 1868 ; LeConte. 1*7(5; riiapuis. ISlid, 1S<;<> ; Eich- 

 hoff, 1878; Hopkins, 18!K',-a and b. 1S!)4 l!M)!)-a and b, 1014, 191 ;>a 

 and b; Hubbard, 1807; Pierce, 1!>!>7; Swaine, 1!)!)!); but foreign 



*The authorities do not always agree in describing male and female characters: we 

 have followed IJr. Hopkins in cases of disagreement. 



