37 



In some years this insect is so very abundant in 

 gardens that it not only causes disfigurement, but 

 materially checks the growth of the bushes. 



It is especially common on the hardier varieties, but 

 will attack all kinds. I have seen it work on Reve d'or 

 and on Moss Roses so ravenously that not a leaf 

 remained intact. 



LIFE-HISTORY AND HABITS. 



The sawfly is much like the former shiny black, 

 the knees, four anterior tibiae and tarsi, white and with 

 smoky wings (Plate VI., Fig. i). Length, one-sixth 

 of an inch. The adults occur first in May, when the 

 females lay their eggs in the mid ribs of the leaves. 

 The larvae are pale yellowish green, with a darker line 

 down the back, marking the alimentary carial. The 

 head is more or less bright orange. When mature they 

 fall to the ground and pupate in the soil in small 

 oval cocoons. 



At least two broods occur during the year. The first 

 larvae are seen in June, the second brood in August; and 

 in 1907 they occurred in September. 



This insect is not only very common in gardens in 

 Britain, but also in France, Germany, Holland, Sweden, 

 Denmark and North America. 



TREATMENT AND PREVENTION. 



It can easily be killed by spraying the Rose bushes 

 with hellebore wash, which is better than dusting the 

 hellebore powder over them. 



If there has been a bad attack it is well to have 

 as much as possible of the surface soil removed in winter, 

 and either deeply buried or burnt and fresh mould put 

 over the roots. 



