CO LEO FTE It A SCOLYTID.*]. 



125 



As this beetle has proved a veritable pest on the Continent, and 

 also occasionally in this country, it would be well to guard against its 

 ravages. Perhaps the best preventive would be to remove or burn 

 all comparatively young fresh branches which would come in prox- 

 imity with any fairly large coniferous trees planted out, either in 

 parks or villas, for immediate effect. 



Genus Trypodendron. 



The beetles of this genus are entirely different in their workings 

 from the sections hitherto considered. The Trypodendron mother- 

 beetle bores directly into the stem of the tree for about \ to f inch 

 deep, directly towards the centre or pith, but when this depth is 



Pig. 122. Block of wood shown in perspective to illustrate the workings of the genus 

 Trypodendron. (After Eckstein, and copied from Niissliii.) 



reached she bends slightly round and then bores in a somewhat 

 curved direction, parallel to the circumference of the tree, and always 

 preferring the sap-wood. After she has taken the bend referred to 

 she makes a sort of recess or basket, alternately right and left, of the 

 main gallery, and places a single egg in each recess. In due time 

 the eggs hatch out and make short galleries at right angles to the 

 parent gallery. Each gallery points upwards or downwards. As 

 regards space, each gallery alternates, and thus Ave get "ladder 

 galleries" formed. When fully developed, the offspring creep out 

 at the entrance made by the mother-beetle. 



The accompanying figure, fig. 122, taken from Niisslin, is a sort of 

 perspective representation of an infested block, and gives a very good 

 idea of how the insect bores into the stem. 



The generic characters are : Eyes divided in two parts ; knob of 



