COLEOPTERA SCOLYTID.E. 91 



some very suggestive points. For example, the white, footless, taper- 

 ing larvae associate the thought of adaptability for tunnelling ; and 

 the circular form of the body, the short antennae, buried head, and 

 stout legs of the adult, eloquently proclaim the suitability for boring 

 and clearing out the bore dust without injury to, or obstruction from, 

 the appendages. 



There is also another very suggestive problem — viz., the association 

 of the male and female in the same burrow. It has been noted that 

 copulation may take place outside the main entrance or, as a rule, 

 just immediately inside the entrance, where a special chamber, known 

 as the chamhre de copulafrix, is formed. After fertilisation the female 

 makes a burrow, in which she deposits eggs right and left in miniature 

 recesses. The male remains behind, and either guards the female or 

 the eggs against natural enemies, or clears out the frass or bore dust 

 excavated by the female. In a single-armed gallery the sexes may 

 therefore easily be determined by position, inasmuch as by following 

 up the gallery from the entrance we come first upon the male, and 

 afterwards the female. Such is the method in a single-armed gallery ; 

 but in many cases the gallery is double-armed, and the female works 

 one arm at a time, then retires and works the other arm. N"ow, why 

 this double arm % and why this second working shift 1 Is it possible 

 that it may be for re-copulation? We know that in some insects 

 this is an essential for reproduction, as, for example, in the case 

 of Hylohius ahietis, and it may be possible that such is the case in 

 certain species of Scolytidse. This is only a suggestive thought, 

 but doubtless much may be learned by observation in this sphere of 

 entomology. 



As regards general measures for getting rid of the beetles, various 

 suggestions have been offered ; but seeing that, as a rule, they only 

 attack dead or dying trees, it is obvious that the best preventive 

 measure would be, either to keep the plantations as healthy as possible 

 or to get rid of the dead and dying trees. Branches should always be 

 burned, and, as far as practicable, when the insects are in the larval 

 stage. 



With a view to collecting the lieetles for the purposes of scientific 

 study, it is well to cut down certain trees or branches and leave them 

 on the ground, to act as decoy stems or traps ; and in searching for 

 certain species it is often advisable to look on the under side of the 

 branch and in places Avhere the ground is rather moist, — moisture 



