REPORTS BY THE HONORARY SCIENTISTS. 153 



for a considerable time is true enough, and in my experiments 

 with palliatus I have found the newly issued imagines making 

 their tunnels and laying their eggs in the very same piece of stem 

 in which they themselves had been bred, although this had been 

 dead for long. At the same time, in another experiment, where 

 I placed palliatus on freshly-felled healthy pine, kindly sent to me 

 for the purpose by Mr Mackenzie of Mortonhall, the beetles 

 bred and gave rise to a new generation. 



The adult females set about egg-laying in March, or, in a late 

 spring, in April, Having bored into the bark, the adults make 

 a main gallery, which runs longitudinally. The tunnel, when 

 finished, is from one and half to over two inches long, and is some- 

 what bent ; at its beginning it is shaped like a crutch or a boot. 

 When this tunnel is being made, both the male and the female beetle 

 are to be found in it. Along the sides of the tunnel eggs are laid 

 in little hollowed out pits, and the grubs, when hatched, tat out 

 galleries which at first are at right angles to the mother-tunnel, 

 but later run longitudinally or irregularly, while they often cross 

 one another and interlace. The full-fed grub pupates in a little 

 bed, which may be hollowed out either in the alburnum or in the 

 bark. The ripe beetles eat their way to the outside, their flight- 

 holes showing as if the stem had been riddled with small shot. 



There are two generations in the year. In my experiments the 

 April beetles gave rise to a new generation which appeared in the 

 beginning of July. Some of this brood I placed on fresh material 

 from July 14th to July 19th, with the result that new beetles 

 issued towards the end of October. The length of one cycle, that 

 is from one egg-laying till the issue of a new brood, varies 

 according to the weather from less than three months to over 

 three months. Should late autumn or winter, however, overtake 

 palliatus while still in the grub condition, the length of the cycle 

 will be considerably increased, as during the winter months the 

 grubs make little or no progress, but remain in a condition of 

 hibernation. 



The best method of fighting against palliatus is to prepare a 

 series of trap stems, beginning in March and continuing up till 

 October. In 1898 I first got the beetles early in April, and 

 every month thereafter up to and including October. The traps 

 which palliatus will make use of to breed in should be examined 

 and destroyed, with the enclosed brood, at intervals, say, of not 

 more than six weeks from the time of preparation. Mr John 



VOL. XVI. PART I. L 



