196 transactions of royal scottish arboricultural society. 



Description of Insect. 



Moth. — The moth is very small, measuring only 4 to 5 milli- 

 metres (less than one-fifth of an inch) in length and 10 to 12 

 millimetres in spread of wings. The forewings are silver-grey 

 and silky, with a gloss like lead ; the fore-edges are somewhat 

 darker ; the fringes of these forewings are grey or brownish- 

 grey. 



The hind wings are dark grey and not so glossy. The face 

 is white ; the base of the antennae is white, and the rest of the 

 antennae dark and light-ringed. There is a tuft of hairs on 

 the head ; the colour of the hair is given differently by different 

 Continental authorities, in my own specimens the colour is 

 yellow. The abdomen of the moth is dark grey. 



Caterpillar. — The larva is pale yellow when young, but later 

 is pale grey, with a dash of red, and is dark striped towards 

 the hind end of the back. The head and the three front pairs 

 of legs are black. The length is 6 to 7 millimetres. 



Pupa. — The pupa is dark brown, with a black head ; its hind 

 end is distinctly pointed. 



Distribution. ~'X^\\^ moth is native to Eastern Germany, the 

 Alps, and Holland. 



Life-History. — The moths issue, through an already prepared 

 flight-hole in the twig, at the end of May and the first part of 

 June. The eggs are laid then on the lower part of the shoot of 

 the year, one &^,g being laid for each shoot chosen. The ^^g 

 soon hatches. At the time the caterpillar hatches out and 

 starts feeding, by boring below the epidermis, the new larch 

 branch is still developing, and the feeding of the caterpillar at 

 this early stage is not sufficient to prevent the shoot reaching 

 its normal length. As the year goes on, the damage is greater, 

 owing to the increased size of the caterpillar and its more 

 extended feeding. Winter overtakes the caterpillar before it is 

 full grown, and hibernation takes place in the boring it has 

 made. The borings or galleries are partly filled with black 

 excrement and bore-meal. 



In late March or in the month of April the caterpillar starts 

 feeding again, destroying right to the wood and ringing the 

 shoot to an extent — in the longitudinal direction — of four-fifths 

 of an inch. The twig dies above this place of ringing. 



The caterpillar is full-fed in May, and previous to its pupation 



