HYMENOPTEEA (SAWFLIES). 191 



July ; they have a black-and-yellow-banded body, brighter in 

 the male than in the female ; the former sex is rather more 

 than one-third of an inch long, the latter slightly smaller ; wing 

 expanse just over half an inch. The female cuts, by means 

 of her saw-like ovipositor, a slit just beneath the developing 

 ear of corn, and there places a single egg, closing the hole up 

 as others do in this group. In two weeks, or a little less, 

 there comes from the ovum a small white larva, which at 

 once commences to devour the inner parts of the straw : as 

 the larva grows it works downwards, until about harvest-time 

 it has reached the bottom of the straw, having eaten its way 

 through the successive nodes. When mature it reaches half 

 an inch in length ; it is white, and, unlike other Sawfly larvae, 

 it is nearly apodal : a few small lumps below are all that 

 remain of the typical sucker-feet. When the bottom of the 

 straw is reached the larva turns round, and then cuts the straw 

 off an inch or two above the ground as clean as if cut with a 

 sharp penknife. The winter is passed in the stubble, where the 

 larva spins a cocoon of pale loose silk, pupating in the cocoon 

 in the very early spring. Some live in wild grasses at the 

 headlands, hedges, and woods, so that we have constant fresh 

 infestations coming. 



Prevention. — If the stubble is simply ploughed in after an 

 attack of corn sawfly, unless very deeply, a large number of 

 the insects will hatch out and escape from the ground. It is 

 advisable where this pest has been very bad to scarify the fields 

 and harrow the stubble together and burn it : by so doing all 

 the larvEe in the "grattcn" are destroyed, and thus subsequent 

 harm prevented. 



Many other Sawflies are often injurious, including the Apple- 

 Sawfly (Hoplocampa testudinea), which eats the young apples, 

 and the Pine Sawfly {Lophyrus pint), which is sometimes most 

 injurious in pine-forests, and the Large Larch Sawfly (Nematus 

 erichsoni). 



