FAMILY SCOLYTIDAE 501 



POLYGRAPHUS. 



An important genus containing several serious coniferous pests in the 

 North-West Himalaya. 



Polygraphus major, Stebbing. 

 (The Blue Pine Polygraphus.) 



REFERENCES. Stebbing, Depart. Notes, i, p. 234 (1903); id. Ind. For. Mem. Zool. Set. vol. i, pt. i, 



p. 6 (1908). 



Habitat. North-West Himalaya. 



Trees Attacked. Blue Pine (Pinus excelsa) ; Spruce (Picea morinda) ; 

 Deodar (Cedrus deodar a}. Jaunsar, Simla, Kumaun, Tehri Garhwal, Chamba. 



Beetle. Oblong, sub-cylindrical. Head and prothorax black, shining. Elytra chest- 

 nut brown to black, covered with a short dense greyish or yellowish pubescence very charac- 

 teristic of the beetle. Antennae yellow, club chestnut brown with a 

 Description. grey pubescence. Legs chestnut brown to black (more usually the 



latter), tarsi yellow. Head with an almost circular brush of longish 



yellow hirsute hairs on the front, the hairs pointing inwards ; an irregular brush of similar 

 hairs beneath the eyes and extending along the base of the mandibles. Prothorax sub- 

 cylindrical, wider at the base than long, sharply constricted anteriorly ; a fine median shining 

 longitudinal carina variable in thickness and a narrow transverse channel in the anterior fourth, 

 separating the anterior fourth, which is constricted, from the wider posterior portion ; rugulose- 

 punctate on disk and sides with the exception of a circular area on latter, which is smooth and finely 

 punctate ; the lateral edges and posterior outer angles coarsely rugose, with a short yellow 

 pubescence which extends along posterior margin. Elytra twice as long as prothorax and 

 two-thirds as wide as long, scarcely dilated towards apex ; finely striate-punctate, the sutural 

 stria most prominent, and others more prominent basally, disappearing apically ; basal area 

 rugose, the margin with a short dense whitish-yellow pubescence ; this pubescence covers the 

 whole of the elytra in living specimens, often giving them a greyish appearance; the basal 

 and apical areas are often, however, found to be bare, the villosity having been worn off during 

 the tunnelling operations of the beetle. Abdomen black, shining, punctate, the punctures 

 densest on the apical segment ; posterior edges of the segments fringed with yellow hairs, 

 densest medianly. Length, 3.2 mm. to 3.8 mm. (PI. xlvi, fig. i.) 



$ Smaller than $, the prothorax more finely punctate, with a finer median carina, and 

 the posterior angles more pubescent. Elytra with a finer punctation and finer pubescence. 

 Length, 2.8 mm. to 3 mm. 



Egg. The egg is small, elliptical, with blunt ends ; it is semi-translucent, the ends being 

 quite translucent. Length, 0.75 mm. 



Larva. When newly hatched it is semi-translucent with a pale yellow head and yellowish- 

 brown mandibles. The segments are marked dorsally, the abdomen tapering sharply. The 

 full-grown larva is white, curved, legless, with a yellow head, followed by enlarged prothoracic 

 segments. These and the abdominal segments, which taper posteriorly, are corrugated, soft, 

 and bulky. Length, 3 mm. 



Pupa. Whitish yellow, broadest medianly, the head hidden by the thoracic hood ; wings 

 and legs pressed against the ventral surface. 



The beetle appears on the wing at the beginning of May at elevations 

 of 8,000 feet, and during late April at lower altitudes, 

 Life History. and may be found at these periods pairing and oviposi- 

 ting in the trees. The insect appears to pass through 

 the winter either as a mature beetle or as an over-wintering larva. If the 



