115 



Host tree. — Recorded by Hopkins from PiJius radiata (Monterey 

 Pine). 



Distribution. — Our specimens are from California, some from San 

 Diego county. We have a series from British Columbia j^ellow pine that is 

 barely distinct from plastographus type, but is left at present in integer. 

 Probably we have to deal with only one variable species. 



Ips perturbatus Eichh.; Berl. Ent. Zeit., 247, 1868 (Tomicus); Rat. Tomic, 

 248, 1878; Ips hudsonicus Lee; Proc. Am. Phil. Soc, 15: 366, 1876 

 {Tomicus). 



Length, 4 mm. to 5-5 mm. Distinguished from its allies by the stout 

 form and usually large size; long, erect, abundant pubescence; short and 

 stout pronotum; the punctuation and pubescence of the first two elytral 

 interspaces; the deep, wide and posteriorly widened sutural striae; the 

 usually convex interspaces, and the stout rather short declivital armature^ 

 The male has the third declivital tooth more acutely pointed. 



Host tree. — We have taken this species only in White Spruce. 



Distribution. — Newfoundland, Quebec, Ontario, and across Canada, 

 extending north of the prairies in Saskatchewan and Alberta to the Peace 

 river, and through northern British Columbia into the Yukon. It appar- 

 ently follows the northern range of its host tree. Back's " Bostrichus 

 typographus Fabr.," taken on the Great Fish River, was probably this species. 



An important secondary enemy but apparently at times of primary 

 importance. 



Ips avulsus Eichh.; Berl. Ent. Zeit., 402, 1867 (Tomicus); Rat. Tomic, 225, 

 1878. 



Length, 2 • 8 mm. This very small species is apparently limited to the 

 southern portion of the United States. It is distinguished from its allies 

 by the small size, more feebly developed declivital armature, with the last 

 three teeth subequal, the dechvity less excavated, more strongly oblique, 

 and the apical margin 'but slightly produced. 



Ips pini Say, Jour. Acad. Nat. Soc. Phil. 5: 257, 1826;- ed. Lee. 2: 319 (Bos- 

 trichus); Leconte, Am. Phil. Soc. Proc. 15: 363, 365, 1876 (Tomicus); 

 Eichhoff, Rat. Tom., 252, 1878 (Tomicus). 



Length, 3-5 mm. to 4-2 mm.; the front convex and coarsely granulate; 

 the pronotum slightly but evidently longer than wide, finely punctured 

 behind, the punctures smaller towards the middle hne, finely, closely, 

 acutely, subconcentrically asperate in front, the sides slightly, arcuately 

 narrowed on the basal three-fourths, emarginately narrowed on the cephalic 

 fourth and narrowly rounded in front; the elytral striae usually slightly 

 or not at all impressed, with the strial punctures small, the sutural striae 

 usually but little more evident, the declivity with the 2nd and 3rd teeth 

 acute and similar. The 77iale has the front more coarsely granulate, and 

 the 3rd declivital tooth longer, stout, and slightly curved. There are 

 frequent variations in nearly all the external characters; the pronotal 

 punctures vary from moderate in size to small, and nearly obsolete on the 

 middle line; the sides are sometimes distinctly angled at the cephahc fourth; 

 the sutural striae and less often the other discal striae are sometimes distinctly 

 impressed, and the elytral punctures are sometimes moderately coarse. 

 The majority of the specimens in our very large collection conform to the 

 characters given in the key. 



The egg-tunnels radiate from a central nuptial chamber, in number 

 from three to six, engraved on the inner bark and deeply on the wood 

 surface; the eggs are placed singly in niches; the larval mines are mainly 

 on the inner bark, usually short and rapidly widened, the pupal cells en- 

 36198—81 



