FAMILY SCOLYTIDAE 



sides, is grooved out, and in this two beetles, 

 a male and female, are always to be found ; 

 and this is probably the pairing-chamber. 

 After pairing the male leaves the chamber 

 by the hole of entrance, and the female 

 commences boring her egg-gallery. This 

 is merely a straight continuation of the 

 pairing-chamber, and is always parallel 

 to the longitudinal axis of the tree. Small 

 recesses are eaten out on either side close 

 together all up this gallery, and an egg laid 

 in each. The first eggs hatch out before the 

 female has completed her gallery and egg- 

 laying, so the egg-stage is evidently a short 

 one lasting but a few days at most. The 

 female blocks up each recess with wood-dust 

 after laying an egg in it, probably to provide 

 a first meal for the newly hatched larva. 

 The egg-gallery is kept quite free of wood- 

 dust. An examination of old galleries will 

 show that the larvae bore away from the egg- 

 gallery in a radiating manner, the pattern 

 formed by their collective galleries approach- 

 ing an ellipse. When full-fed the larvae 

 enlarge the end of their galleries and pupate 

 in these chambers. When mature the beetle 

 bores its way straight out of the tree by a 

 hole through the bark. The length of the 

 egg-gallery is five-eighths of an inch to two 

 inches, with a breadth of a quarter of an inch 

 or less. Length of larval galleries one-third 

 to one and a quarter inch. Breadth one- 

 eighth inch at top and one-sixteenth inch 

 at base, where they take off from egg-gallery. 

 The number of eggs laid by the beetle averages 

 t\venty-four. The plan of the gallery is very 

 like that of S. siwalikensis, shown in fig. KJ. 



I consider it probable that there are at 

 least three generations of this beetle in the 

 year and perhaps four. Some green .l>t<>- 

 geissus poles felled in April and left lying in 

 the forest were examined on 6 August. They 

 were found to have been attacked from top 

 to bottom by this beetle since they had been 

 felled. The insects had laid their eggs in 







Ki<;. 323., lji<>,-i.iMt v /tit if <> lia pole 

 infested by Sphaerotrypes ciumha- 

 A vv;/ .*/.-, Steb., showing the exit-holes 

 "I ,i matured generation of beetles. 

 Coimbatore, Madras. August 1902. 



