DISTRIBUTION OF INDIAN FOREST INSECTS 



differs greatly from that in the Eastern portions of the range. And this 

 is only what might be expected, since the composition of the forest in the two 

 localities is entirely different. In the Western Himalaya, as compared with 

 the broad-leaved assemblage 

 of species characteristic of 

 the Eastern, the coniferous 

 forests predominate, and we 

 find classes of pests more 

 resembling those of the 

 European, American, or 

 Japanese coniferous areas. 

 Here again anomalies are 

 found in the distribution of 

 genera and species, and 

 even families. The impor- 

 tance of the families Bos- FIG. i.SfAenoptera aterrtma, Kerrem. 

 trychidae, Buprestidae, and d i natural size, d e enlarged. 

 Cerambycidae, all powerful 



groups in the plains, has disappeared. Serious pests, small in size, there 

 are in the two latter families, as witness the deodar buprestid Sphenoptera 

 atcrriina and longicorn Trinophyllum cribyatum, and the long-leaved pine 

 Nothorrhina. But the great importance of the families as evidenced in the 

 plains forest has been outclassed here by the Scolytidae. This family in 

 the Western Himalaya contains an assemblage of pests who have at their 

 mercy the whole of the coniferous species, and in even" instance, so far 

 as present investigations go, the species affecting a particular tree accom- 

 panies it from the centre to the limits of its habitat. Another point 

 about the distribution of some of these genera, which is known to be 

 the case in other parts of the world, is that one or more appear to be 

 confined to a particular species of tree. There are, e.g., three species 

 of Scolytus known in the Western Himalaya (5. nntjor, S. minor, and 

 S. deodar a), and they all infest the deodar. I have never yet taken the 



genus from any other tree in the 

 Himalaya, nor have I found it at all 

 in the plains. And \ et in Europe the 

 genus is confined to broad -leaved tree- ' 

 \\'e must look to America lor analo- 

 goiis instances of its infesting com! 

 There is a / Wv^n//>//;rs (!'. W it is 



true, \\lneh will also infest the de. idar, 

 -.. 4 . Polygraph i major, Steb. X 16. but only wlit-n it is unabl* 



sufficiency of its own real host, the 



blue pine. The important genus Fomicus, on the other li.m.l 

 appear to infest the deodar. One species (T. n/> 

 blue pine (often in company with I'oly^niplins />/;//) and spruce ibut not 



