50 INDIAN FOREST INSECTS 



In all cases the result is the same. The value of the timber, firewood, 

 or bamboo is greatly reduced, or the material is so riddled as to be useless 

 for all purposes save that of inferior firewood. Considerable loss has 

 occurred in various wood depots throughout the country, and especially at 

 the fuel depot of the Changa Manga plantations, in days past. Fuel stacks 

 seen here consisted principally of masses of wood powder owing to the 

 severe infestations by the two beetles Sinoxylon crassuui and S. anale (fig. 27). 



In cases of bad infestations of this nature the only chance left of 

 thoroughly clearing the depot is to burn completely the whole of the infected 

 material, and this must be done at the period when the insects are in their 

 larval and pupal stages in the wood, and not at the periods when the insect 

 is on the wing in the depot. In the former case you will get rid of the 

 pest in one operation, or so reduce its numbers that it will not assume the 

 importance of a pest for some time to come. 



(3) Insects which Oviposit or Pupate amongst Dead Leaves on the 

 Forest Floor or in the Humus or First Inch of the Soil.— A number of 

 insects are now known which pupate on or a little way beneath the upper 

 layers of the forest floor, amongst the dead leaves, in the humus, or in the first 

 inch of the soil. To mention a few : The teak defoliators Hyblcea puera and 

 Pyrausta machaeralis act in this way, so does one at least of the conifer cone 

 destroyers {Enzophera and Phycita). The deodar defoliator {Geometrina? sp.) 

 acts in the same manner, as also the Boarmia defoliator of the sal-tree 

 in the United Provinces Terai. Again, almost all the seeds of forest trees 

 at present known to be infested by insects fall to the ground from the trees 

 when the grub has nearly or quite reached full size. The grub then either 

 leaves the seed and burrows into the humus layer, or pupates within the 

 seed. The latter, however, is now on the forest floor ! Examples of such 

 are : — The sal-seed destroyers {Conogethes, Laspeyresia, etc.) ; also the Alcuics 

 weevil of the walnut, the Callirhytis fly of the kharshu oak {Q. scmicarpifolia), 

 and the Calandra weevil of the ban oak {Q. incana). 



The weevil sissu-leaf defoliators (Apoderns) also pupate amongst dead 

 leaves on the soil, the little leaf-roll in which the larva feeds falling to 

 the ground. 



Again, some insects oviposit amongst the dead leaves on the ground or 

 amongst stones, pieces of fallen wood, etc., on the forest floor. Of such is 

 the MonopJilebiis scale of the sal-tree. This insect lays over six hundred eggs 

 in a loose silken sack on the ground amongst leaves or beneath stones, pieces 

 of wood, etc., and lays them at the very period (April and May) when the 

 sal-defoliating Boarmia is pupating in the soil. Thus we have two serious 

 pests in a quiescent stage in a place where they can be got at at the same 

 time. And there is another class of pest in these forests, several species 

 of melolonthid grubs {Lachnosteyna, Hdcroplia, p. yj), which is to be found 

 feeding on the roots of the sal-tree or in the pupal stage within the first 

 inch of the soil layer at this period. 



