21 



a piece of sheet-celluloid, leaving a very small opening at one side of the nuptial- 

 chamber for ventilation and the extrusion of the boring-dust. Better results 

 are obtained with but one egg-tunnel, since in sets with several working females 

 more dust is pushed into the nuptial-chamber than the male can handle under 

 the abnormal conditions, and the chamber rapidly becomes blocked. With 

 such an arrangement one may observe the removal of the boring-dust and its 

 extrusion from the nuptial-chamber, the feeding habits of the male, copulation, 

 and the reversal of position of the female before and after egg-laying. If the 

 roof of the egg-tunnel is rapidly and carefully removed immediately after the 

 female has been observed to back into the tunnel, the process of egg-laying may 

 be studied. A bit of sheet-celluloid should be placed over the tunnel as soon 

 as it is opened. 



When the bark is thick, and the tunnels chiefly in the inner bark, the 

 following method may be used with advantage. The bark is carefully removed 

 from the wood, leaving the nuptial-chamber and the developing egg-tunnel as 

 nearly uninjured as possible, with the beetles wnthin them. A small sheet of 

 moderately thick glass is placed over the inner side of the bark, closing in the 

 tunnels. The glass should be held firmly in place by rubber bands or other 

 means. When the tunnels are not under observation, the bark should be kept 

 glass downwards upon dark cloth and weighted moderately with a block of wood 

 to prevent warping. 



Whether celluloid or glass is used to cover the tunnel, the male will imme- 

 diately proceed to fasten all cracks about the edges of the chamber with boring- 

 dust, and the female does the same in the egg-tunnel; excessive evaporation 

 from the opened tunnels is thus somewhat checked. It is necessary to remove 

 the glass or celluloid from time to time and clean away the boring-dust which 

 has become attached to it. 



The moisture content of sticks used in breeding experiments may be pre- 

 served to some degree, while the bark is intact, by coating the cut ends with 

 melted paraffin. 



Fig. 1 — EccoPTOGASTER RUGULosus Ratz. 



Tunnels at right; adult above, viewed from the 

 side, legs removed. (Author's illustration.) 



