A HISTORY OF ESSEX 



resulting larvas, which are speedily developed, are so numerous and 

 voracious that they soon make extensive clearances in all directions. In 

 17823 many thousands of acres were destroyed by them, and in 18356 

 our own county suffered very severely from their ravages. At a later 

 period they devastated the fields in the neighbourhood of Tollesbury, but 

 happily their visits are few and far between, and during many recent 

 years entomologists who have been desirous of obtaining specimens for 

 their cabinets have sought for them in vain, though a few were obtained 

 in Essex, Suffolk and elsewhere in 1900. It is said to feed also on 

 charlock and to prefer that plant to turnip when there is a sufficient 

 supply. 



The Gooseberry Sawfly (Pteronus ribesii) is also occasionally very 

 destructive to the currant and gooseberry crop. A few years ago it 

 entirely denuded all the bushes about Colchester of their leaves, but the 

 disease speedily produced its own remedy, for so numerous were the 

 larvae that they consumed all the available food long before they reached 

 maturity, and apparently the whole brood perished from starvation. 

 After leaving the naked bushes they wandered about seeking vainly for 

 food elsewhere, and at this time the pathways in the neighbourhood of 

 market gardens were black with their dead bodies, which for several days 

 emitted a sickly odour that compelled attention. 



Another species (Hoplocampa testudinea) deposits its eggs in the 

 apple blossom, and the larvas feed in the young fruit, causing it to fall 

 when about half-grown. Probably the damage thus done is generally 

 set down to the Codling Moth (Carpocapsa pomonella) for both feed after 

 a similar fashion ; the Sawfly however does not seem to be very 

 abundant, at least in north Essex, and has only been found there in the 

 early summer fruit. As soon as the fruit falls to the ground the larvae 

 proceed to make themselves scarce, so that many apples may be opened 

 and few larvas found, and as these are by no means easy to rear, the insect 

 is very scarce in collections and probably few entomologists have ever 

 seen it. 



The Corn Sawfly (Cephus pygmceus) is another insect with an evil 

 reputation on the continent, its larvas feed in the interior of corn stems, 

 but any damage they may do in this country is seldom if ever brought 

 home to them, though seeing how very abundant the perfect insect is in 

 our own fields in the early summer, one would think it must be to some 

 extent injurious. The two species of Sirex (S. gigas and S. juvencus) are 

 large handsome insects with powerful ovipositors adapted for boring into 

 the solid wood of fir trees, to which they are accused of being very 

 destructive. In this country they are far from common, and though 

 they are sometimes met with about Colchester they never there attack 

 healthy standing trees, but only such as are dying or have been felled. 

 No doubt they do attack larch and spruce posts and take possession of 

 any trees that have been left unduly long on the ground after they have 

 been felled, and speedily render these good for nothing but firewood. 

 Many of the Sawflies are very beautiful, and the problems connected 



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