488 FAMILY SCOLYTIDAE 



This Sphaerotrypes infests the sal and Terminalia toinentosa of the Central 

 Provinces and Chota Nagpur sal areas, and takes the 



Life History. place of the 5. siwalikensis in the United Provinces 

 and the ussiiincnsis in Assam. Its method of attack in the tree, plan of 

 galleries, and life history are very similar to those of these two latter insects, 

 with some points of difference due to climatic peculiarities of its en vironment. 



The first beetles of the year make their appearance in February, and 

 oviposit in felled trees, wind-blows, or in standing green sickly or dying 

 trees in the forest. The male beetle fertilizes the female inside the tree. 

 The male bores through the bark down to the sapwood, and eats out there 

 a short gallery from a third to a half of an inch in length, and parallel to the 

 longitudinal axis of the tree. A female enters by the entrance-hole of the 

 male in the bark (enlarging it, as the female is larger than the male), is 

 fertilized in the small tunnel in the sapwood, and then proceeds to eat out 

 a prolongation of this pairing-chamber, the direction remaining the same. On 

 either side she eats out small indentations, in each of which an egg is placed. 

 The development of larvae is similar to that of the other Sphaerotrypes beetles 

 known, save that the larval galleries appear to be of shorter length. The 

 larvae, when full-fed, appear invariably to pupate in the bark, eating out a 

 cup-shaped depression in the thick bark at the end of their galleries. 



The number of eggs laid is from twenty-five to thirty on each side, fifty 

 to sixty in all per female. The length of the egg-gallery is from just under 

 i in. to ij in. It is shorter when made low down in the main stem than 

 when made in the smaller branches. The larval gallery is from 2 in. to 

 2.\ in. in length. The pattern left by the egg and larval galleries in the 

 bark is similar to that left by siwalikensis, and is shown in pi. xliv. 



We have seen that a generation of beetles appears in February and 

 oviposits. The beetles maturing from these eggs appear in April, giving 

 seven to eight weeks for the generation, and may be found laying the eggs 

 of the second generation of the year in the latter half of April. The 

 number of generations in the year has not yet been definitely ascertained, 

 but it will not be less than four. 



The life history, as detailed above, shows that the insect is a generation 

 ahead of siwalikensis in April, since the first beetles of the year of the 

 latter only appear in this month, the long cold winter in the north 

 accounting for the difference. 



The life history of the insect in the Terminalia toinentosa is similar to 

 that in the sal. Owing to the bark of this tree being somewhat thinner, 

 to its drying quicker, and to its being whiter inside, the galleries of the 

 insect are more clearly defined than in the sal. (Cf. plates xlii and xliv.) 



I first noticed the attacks of this insect in the Chota Nagpur sal forests 



between the years 1894 an d 1897. In 1909 I had an 

 Damage Committed .^ J r . . ,.,.;. 



in the Forest. opportunity of studying its life history in the Mandla 



division of the Central Provinces. My visit was at an 

 opportune time, since, in addition to the cold-weather fellings, a new road 



