246 HEMIPTEEA-HOMOPTEEA. 



in the folds of the buds, and there in their immature form they 

 suck the sap and prevent the leaves and blossom from develop- 

 ing. The larvae are flattish creatures which we find in the buds, 

 having crawled thither after their exit from the egg. They also 

 block up the buds with their honey dew. They are greenish in 

 colour, with red eyes. A true pupal stage is assumed, bud-like 

 wings appearing, until by the end of a month after their escape 

 from the egg, wings are fully formed. The pupse have brown 

 markings on them. The winged Psylla has four transparent 

 wings, and is usually seen about the second week in June, the 

 female being brighter than the male. In size they vary from 

 I to yV oi an inch. We may find larvcB as late as October, 

 but the majority are mature by September, when they pair and 

 deposit their eggs, two or three in a row, yet separate, upon the 

 youngest apple-shoots amongst the soft hairs. These eggs can 

 easily be seen in the winter, as they are lohite, pointed at each 

 end. It is stated that they go on laying until November. 



Prevention and Remedies. — It is advisable to wash the apple- 

 trees, especially the early kinds, after picking, with a paraffin 

 emulsion to stop egg-laying. Caustic winter washes soon destroy 

 the delicate eggs, and thus there is no cause for early spring- 

 washing, as far as this pest goes. Another lives on pear-trees, 

 called lAvia pyri, a red long-winged species. 



Snow-plies (Aleyrodid^). 



These are also Hemiptera. They are small, moth-like, snowy 

 white, four-winged insects, with a single vein only in the front 

 wings, and their body covered with a fine white mealy powder. 

 The pupa, unlike other Hemiptera, is inactive, and enclosed in 

 the dried skin of the larva. The commonest species is the 

 Cabbage Snow-fly {A. proletella), found at all times of the year 

 on cabbages, beneath the leaves, where they suck out the sap 

 with their beaks, forming brown and yellow patches on them. 

 The eggs are laid in a patch on the leaf and hatch out in ten 



