Insects, etc., Injurious to the Plum. 



391 



The adult (Fig. 2(11) may 



THE OAK AND FRUIT LEAF HOPPER. 



{Typlilocyha quercus, Fabr. = TypMorylm Jiamriiigera, Amyot.) 



Like all members of this family, the insect passes the winter in 

 either the adult or nymphal stages. Hibernation takes place in any 

 sheltered position. One may find them amongst fallen leaves at the 

 foot of hedgerows, in box hedges, amongst moss and lichens on trees, 

 and abnndantly amongst conifers. In spring they appear again, and 

 feed upon the young leaves. In June they are first noticed in 

 numbers ; possibly between their exit from winter quarters and June 

 a generation appears. It is not until July that any marked 

 damage is done to the leaves of apple, plum and damson ; then all 

 stages of the insect can be found at once, 

 be told by its beautifully-marked an- 

 terior wings, with six bright orange and 

 vermilion spots, on a milky - white' 

 ground, and with a large dusky net- 

 work at the apex. 



Their length varies from 3 to 

 3*9 mm. Both nymphs and adults 

 feed mainly on the underside of the 

 leaves, but by no means always. 



They are not very active, and can 

 easily be taken at rest on a dull day. 

 When disturbed they take a leap from 

 the leaf, and then using their wings, 

 often fly a couple of feet or so away. 



Egg-laying seems a laborious task. By means of a saw-like 

 structure the female cuts a slit into the under epidermis, and places 

 one or more eggs just beneath it. A very minute and faint oblong 

 spot marks where they have been laid. 



The ova are very delicate, white, and oblong-oval in form, some- 

 what curved on one side, and blunt at each end. When nearly ready 

 to hatch they may be seen with a strong lens under the epidermis, 

 their position being plainly marked by the dark eye spots of the 

 embryos. Length 0*04 mm. 



Eggs under observation were found to hatch in four days, but 

 how long they had been laid was not known. Slingerland(15) shows 

 that the American Grape Vine Leaf Hopper {Tjiplilocyoa wmes) 

 remains two w^eeks in the egg stage, and it is quite likely this is 

 about the period taken by Typh/ocyha quercus. 



