576 



FAMILY SCOLYTIDAE 



The grubs of the Xipnnins feed on those of the Scolytus. The histerid is 

 black and shining, and has a superficial resemblance to the scolytid. 



Platysoma rimae, Lewis (p. 105). This insect is fairly plentiful in the 

 \Yi-stern Himalayan coniferous region. It is predaceous upon Scolytus major 

 and S. minor, and other coniferous bark- and wood-borers. 



/;,.,//,. Flat, compact, somewhat elongate, black and shining ; all parts of the insect 

 tit well together. Head is transverse and narrow and provided with stout black mandibles 

 and two elbowed antennae, 

 each of which ends in a 

 club. Thorax is wider than 

 long, smooth in the centre 

 with a few scattered punc- 

 tures, these latter more 

 numerous and larger at 

 sides between the two broad 

 shallow striae. Elytra twice 

 as long as thorax, glabrous 

 medianly, with very fine 

 punctures, the sides with 

 three longitudinal promi- 

 nent striae, the surface 

 being punctured between 

 them ; the elytra leave 

 two segments of the abdomen and a portion of a third visible dorsally, these segments 

 an: constricted posteriorly, the surfaces being finely punctured. Length, 4.5 mm. to 

 6.2 mm. 



X8 



;. 362. Platysoma rimae, Lewis, predaceous upon Scolytus 

 major, Steb. North- West Himalaya. 



Life History. The first generation of the year of this histerid beetle 

 is to be found in various species of conifers in May. A second generation 

 has been taken towards the end of June in newly felled deodar-trees which 

 were infested by the Scolytus bark-borers ovipositing in the trees. The 

 histerid beetles were found in the egg-galleries of the bark-borers, and were 

 apparently engaged in laying their eggs in the tunnels. It is probable that 

 the histerid grubs feed on the larvae of the Scolytus and the beetles 

 perhaps on the eggs. 



But little is at present known about the larval and pupal stages of 

 the beetle. I think it possible that the number of generations in the year 

 coincides with those of the Scolytus insects. 



The insect, owing to its abundance in the trees and to the fact that 

 it appears to be predaceous upon several bark-boring beetle pests in 

 the Himalayan region, is evidently of considerable importance in the 

 forest. 



Thanasimus himalayensis, Steb. This clerid beetle has been already 

 fully icribed on p. 508. It is one of the most important of the Scolytus 

 predators, and is commonly to be found flying over or running about on 

 felled or fallen green deodar-trees which are infested by the two Scolytus 

 bark-borers S. major and S. minor. 



