22 Elementary Manual. of Zoology. 
Aphide are usually amenable to the, methods of treatment. noticed 
as applicable against Coccide (see page 20). Those species which do 
not form galls indeed can often be got rid of by very much weaker 
applications, though it is only in special cases that treatment of any 
kind is practicable? 
Psylliida.—These minute creatures are closely related to the Aphid, 
and need not be noticed in detail. Two remarkable Indian species 
are Psylia cistellata, Buckton, which causes the abortion of the shoots 
of the mango tree, and Psylla zstis, Buckton, which may be. recog- 
nised by the characteristic galls it forms upon indigo plants which 
were reported in 1890 as suffering to an enormous extent in Bengal. 
Cicadide.—These well-known creatures produce the continuous 
whirring sound which is so characteristic a feature of hill forests. 
The sound is produced by the male by means of specially modified 
Jateral stigmata which can readily be seen at the base of the hind legs. 
The habits of the group, as observed in the temperate zone, are as 
follows :—The female lays her eggs in the branches of trees, where they 
are said to be to some extent nourished by the sap, the irritation 
which they set up often doing considerable injury to leading shoots, 
The young emerge from the eggs and crawl down to the ground, where 
they live through several years. They feed upon the roots of plants, 
but are not thought to do much injury in this stage of their 
existence. When at last they are full grown they emerge from 
the ground and transform into the winged males and females which 
produce the eggs, The students should examine and sketch some of 
the specimens in the School Museum. 
Fulgorida.—These creatures usually spend the whole of their existence 
upon the food plant, where the eggs are laid and where the young 
wingless larve gradually grow into the winged adult. They are often 
conspicuous insects, but are of little practical importance. 
Cicadellida.—The representatives of this group are much like the 
Fulgoride. The little green species Chlorita flavescens, Habr., which 
is known in Assam as 6d¢ster blight and in Sikkim as green-fly, 
occasionally does 2 good deal of damage by sucking up the juice of 
the tea leaf. Closely allied to it is the mango Jassid (Jdiocerus 
niveosparsus, Leth.), which attacks the blossoms of the mango in a 
similar manner and is said to seriously interfere with the yield of 
1 In the case of the Apbia which attacks. tea bushes to a small extent,in Ceylon, Mr. 
Green writes—“ A weak wash of kerosine emulsion or pbenyle applied with a brush will in- 
stantly kill every Aphis. It should’ be applied either in the evening or on a cloudy day. 
Hot sunshine Qpon leaves freshly drenched with kerosine is apt to scorch them. One part 
of kerosine emulsion to eighty parts of water will make a mixture strong enough to kill 
every Apbis with which it comes in contact; while a still weaker mixture of phenyle, 
one part to two hundred and forty of water, is sufficient for the same purpose.” 
