DISTRIBUTION OF INDIAN FOREST INSECTS 



7 



Fig. 6. — Nipoiiius 

 caiialkollis^ Lewis. 



the Himalayan pines, but two different species of the j^eniis infest the 



three pines — the blue pine, lonj^^-lcaved pine, and the Vinm kliasya of 



Assam and Upper Burma. 



But whilst such marked limits can be placed u}x)n the distribution 



and host-plants of many of the coniferous bark-borinj,' pests in the Western 



Himalaya, the same limits cannot be assij^nied to the distribution of some 



of the predaceous pests infesting them. For instance, the clerid TJuDuisimus 



himalaycnsis preys equally upon all the various 



species of bark- and wood-borers infesting the deodar, 



spruce, blue pine, and long-leaved pine in the 

 Western Himalaya, appearing equally at home 



between elevations of 2,500 ft. and 8,000 ft. A 

 Niponius also (A^ canalicollis, of the family Histeridae) 

 preys upon the larvae and pupae of these bark- 

 borers, and is to be found not only in the above- 

 enumerated conifers, but also in the Pinus geravdiana 

 in the Suliman Mountains in Baluchistan, where 

 it preys upon the Polygvaphns (P. trcuchi) which 

 infests the pine in this locality. A curious distribu- 

 tion, since the genus is a Japanese one. 



It may be mentioned that another member of 

 this genus (A^ andrcK'Csi) is to be found preying upon the sal-tree Sphaero- 

 trypes both in the Siwaliks and United Provinces Terai, in the Central 

 Provinces sal areas, and again in Assam, w^hilst in Coimbatore it attacks the 

 Spliacrutrypes of the Anogeissus. 



Although I would not be understood to say that they do not occur, I 

 have not found the genera Polygraphus and Tomicus in the plains forest, their 

 places being apparently taken by the genus Sphaerotrypes. 



Per contra,' I have not found that the bostrychid genera Dinoderns 

 and Sinoxylon extend to a great elevation, beyond 4,000 ft. probably, in the 

 Western Himalaya. A species of Sinoxylon has been reported from the 

 Darjeeling rf/s^nc^ in the Eastern Himalaya, but the locality is not recorded, 

 and the district extends down to the plains. These two genera appear 

 to be particularly addicted to great heat requirements, either dry or 

 moist. 



From the above brief resume of the distribution of a few of the more 

 typical forest pests it will be apparent that it would be difficult to base a 

 distribution of certain groups of insects or of certain families, genera, or 

 species, either upon the species of trees they infest or upon certain classes of 

 mixed forests in w^hich they attack the predominant species and some 

 of those others which are normally found in mixture with it ; for it has 

 been shown that the distribution of the particular insect may extend far 

 beyond the limits of the predominant tree. Nor is it possible to base a 

 distribution, in the light of our present knowledge, on particular zones of 

 vegetation, such as a hot dry one, hot moist, etc.; for certain species 



