140 



[November, 



imago states. In March last I cut off from thia tree all parts then harbouring the 

 latter insect, — leaving, however, plenty of wood unattackcd, and in this I have 

 since been observing Sinodendron depositing its eggs. On May 23rd I found two 

 burrows, easily detected by the heaps of frass outside, each containing a pair of the 

 beetle, — which, as I left none in or about the tree, were, of course, bred elsewlicre. 

 The burrows entered the exposed rotten wood for a short distance at right angles 

 with the surface, and then turned upwards along the fibres of the wood ; they 

 were three or four inches long, and wider iu places, as if for " shunting." In these 

 and other burrows found afterwards, before any eggs were laid, the female beetle 

 was always at the side of the burrow with her head at its extremity, as if con- 

 tinuing the excavation, and the male always had his head directed towards the 

 opening and often close to it,— the remarkably flat front of his thorax nicely fitting 

 the burrow, and with sawdust sticking to it, as if it were used for pushing out frass. 

 It is not unlikely that the supposed shunting-places may have been eaten out by 

 the male for nourishment. On the same day I found a solitary ? , who had only 

 burrowed her own length into the wood. I replaced her in an artificial burrow 

 made with the knife (after examining burrows, I usually replaced the beetles in this 

 way, but doubt not that my proceedings disturbed them very much). The next 

 day there was a S also in this burrow, and on the 25th I found this pair in cop. at 

 the top of a burrow about three inches deep. On the 24th there was a burrow 

 containing a solitary , just as that of the 23rd contained a solitary $ , and, by 

 the next day, thia burrow contained a pair of beetles, the ? , as usual, furthest in. 

 In opening the burrow I destroyed the of this pair, but on the 28th, two days 

 after, there was another male in the burrow. On the 31st there was a $ only in 

 this burrow, which I accidentally killed : no eggs had been laid. 



On two other occasions I found burrows commenced by males only ; but ray 

 proceedings so disturbed them that they were gone the next day. I believe the 

 normal length of burrow to be four to six inches, but my opening them so often 

 made some of them burrow twelve or eighteen inches. On June 11th I opened 

 the burrow commenced May 23rd by the solitary ? , and found the extremity of 

 the burrow for about three-quarters of an inch tightly packed v^-ith frass or sawdust, 

 in which were four eggs. The ^ beetle had backed close up against the extremity, 

 and the $ was busily excavating a new branch of the burrow, which left the 

 other just in front of the S • On June 2Svd I opened another burrow, in which I 

 found only a ? , excavating a branch. In another was about three-quarters of an 

 inch of tightly packed frass containing nine eggs ; in a third, a smaller quantity of 

 frass with one egg. Probably in both of these cases the ? was bringing sawdust 

 from the new branch of the burrow to put into the one in which oviposition was 

 going on. It appears that the galleries are always excavated by two beetles, and 

 that they meet first after the burrow is commenced ; but what seems somewhat 

 remarkable to me is, that the burrow is commenced indifferently by either the S 

 or ? beetle. The ^ usually, I suspect, when undisturbed, remains until ovi- 

 position is well advanced. 



In a rotten ash-log, just attacked by Sinodendron, I have subsequently found 

 several burrows which enable me to supplement my observations. One of these 

 burrows was a very fine one, about six inches long, besides branches packed with 

 eggs, of which I was able to examine two carefully. These brandies were each 



