1896.] MICROSCOPICAL JOURNAL. 49 



the wood fiber. In doing tliis the ])road end of the cen- 

 tral piece which lies between the saws causes them to 

 spread as they are extended, so that two grooves are cut 

 at once, lying in a v shaped direction from the entrance, 

 and leaving a ridge of solid wood between the two. After 

 finishing the cut, which is about three-tenths of an 

 inch in length, she withdraws the ovipositor, and again 

 forcing it in at the first entrance proceeds to deposit her 

 eggs, which are placed very symmetrically in a direction 

 oblique to the middle partition, a little cavity being cut 

 for each egg, into which it exactly fits. The eggs are 

 about fifteen in number in each groove, and about fifteen 

 minutes is occupied in the whole operation. 



When one set of grooves has been stocked with eggs, 

 she moves forward about half an inch, and begins another 

 and so continues until her Avhole stock of eggs is dis- 

 posed of. 



I have before me a branch containing twenty-one con- 

 secutive cuts, evidently made by the same insect, and 

 holding probably, more than 600 eggs. 



The extremely curious mechanism by means of which 

 these processes are accomplished will be easily understood 

 by inspecting figure 4, which is a transverse section of 

 the three parts constituting the ovipositor, cut at the 

 dotted line e. 



The central piece, a,a,, would seem to be a pair of tubes 

 somewhat triangular in shape, and firmly cemented to- 

 gether in the middle. These cannot be separated, and 

 the tubes have no outlet at the extremity, where the cen- 

 tral piece ends in two. extremely liard, sharp and solid 

 points, as seen in the figure, which no doubt serve an im- 

 portant purpose in cutting the channels for the eggs. 



On each side are seen sections of the two ovipositors 

 b, b, which are bounded on their exterior sides by a hard 

 chitiuous frame, extending for a short space up the in- 



