674 
THE TROPICAL 
AGEICULTURIST. [April 1, 1899. 
betw een the bases ot the first pair of legs, and from 
its extremity the long hair-!ike sucking tubs can be 
extended into the tissues of the plant. The length 
of tha insect and ovisac together is very little short 
of a quarter of an inch. 
The half-grown female is in all respects similar 
in external appearance to the adult insect, except 
for th e absence of the ovisac. It is therefore a 
much less conspicuous insect, and measure* only 
about one twenty-fourth part of an inch in diameter. 
The young larva again does not di£fer rery much 
from the half-grown insect, except in point of size. 
It is however of a paler colour," and the marginal, 
fringe is only very slightly developed. 
The eggs, which are carried within the ovisac 
packed in a cottony material, are at first ^lmo6t white. 
They soon deepen to yellow, then orange, and, just 
before the emergence of the larva, become of a 
greenish tint. 
The male insect, after the first moult, is readily 
distinguishable from the other sex. It becomes more 
elongate and, instead of secreting compact waxy 
processes, envelops itself in a loose woolly secretion. 
Budimentary wings begin to appear towards the end 
of this stage. The pupal (or nymphal) stage is 
only distinguished by the presence of rather longer 
wing pads, and in the greater length of the antennse, 
which are then folded bask along the sides o? the 
body, extending nearly to its extremity. The pupa 
has long, well-developed legs which it can use when 
disturbed, though it usually remains quiescent be- 
neath its wooly covering. 
The adult male is a very graceful little insect, 
of a totally different appearance to the female. It 
is of a slatey grey colour, with very long slender 
antennas, a single pair of grayish wings, and a tuft 
of long white silky filaments at the end of the body. 
The eyes are black and divided into numerous 
facets. It has no mouth, and consequently takes 
no food in this stage, having laid in a sufficient 
store during the larval period. 
LIFE HISTOEV AND HABITS. 
There appears to be a constant succession of broods. 
I have examined infected plants at all times of the 
yeiir, and have always found the insects in all stages, 
from the newly hatched larva to the adult female. 
I have kept individual females under observation. 
Atter the first commencement of the formation of 
the ovisac a period of three weeks elapses before the 
emergence of the first larva, after which the young 
insects hatch out at the rate of about five a day 
for a period of six weeks or more; by which time 
the parent is exhausted and dies, and the earliest 
hatched larvce are mature and commence ovipositing 
on their own account, The length of life of a single 
insect is therefore about fifteen weeks ; but as it 
commences to produce larvas at the ninth week, there 
may be five generations in the course of the year. 
This fecundity is mci'e or less independent of the 
attentions of the male insects, which appear only at 
irregular intervals. It is doubtful whether a genera- 
tion of males is produced even once a year. It is 
remarkable that the true male of Orthezia insignia 
has been recorded only from Ceylon. Supposed 
males have been described and figured both in England 
and America; bat in both these cases the male 
of a totally different insect has been erroneously 
associated with this female. Since the appearance 
of the pest in Ceylon two male broods only have 
come tinder my personal observation — in July, 1894, 
and May, 1898. On both these occasions the male 
insects occurred in enormous numbers, hovering in 
the air like gnats, the silky tufts on their tails 
glistening in the sunlight. In May of the present 
year (1898) myriads of these little flies might be 
seen floating in the air in certain parts of " Lady 
Horton's Walk " and other roads about Kandy. 
It is the female that is responsible for the chief 
damagt, as she continues to pump up sap from 
the plant during the whole period of her existence. 
Unlike most scale-bugs, the Orthesia is quite an 
active insect and able to change its position at will * 
It prefers the young shoots to the older stems, and 
mores upward with the growth of the plant. 
FOOD PLAKTB. 
Although the Orthezia ie popularly known in Ceylon 
as " the Lantana Bug," this is by no means the 
only plant which it affects. It is more particular!/ 
a garden pest, and it was upon the ornamental 
shiubs and plants in the Pfradecija Gardens that 
it first attracted attention. Its adoption of the Lan- 
tana plant is quite an acquired habit. 
It was early noticed that Orthczin had a special 
taste for certain natural orders of plants, Acanthacea, 
liuhiacor, aiid Verhenacem being particularlv appre- 
ciated by the insect. Since its residence with us it 
has very largely increased its list of food plants. 
It would be difficult to give a full catalogue, bat 
the following plants have been noted : — 
Acaiiihaccic :— Crossaudra, Justicia, Thuubergia, Me- 
yenia, Strobilanthes. 
Jlubiactce :— Cinchona, "Coffee" (Arabian and Libo- 
rian), Gardenia, Hamelia, Ixora, and many common 
weeds. 
T'eriCTacea; ;— Verbena citriodora ("Scented Vef 
bena "), Lantana, Stachytarpheta, Daranta. 
Composite:— Tnhoma. ("VfM Sunflower"), Chry- 
santhemum, Achillea, Vernonia, Ageratom (" Goat- 
weed "), and many common weeds. 
Solanacece :— Habrothamnus, Capsicnm, " Tomato." 
Lahiatm :— Coleus, Salvia. 
UiUacece:~"Ota.nge" and various kinds of Citrna. 
Legutninosce : — Clitoria. 
Capri/oliacea i—ljoaiceia, (" Honeysnckle "). 
liu/noniacem : — Tecoma. 
Itosaceae : — " Strawberry.'' 
Amaranlhacea: : — Iresine. 
Tenistromiaccoc : — " Tea. ' 
Convolvxlacece : — Ipomea, 
Lythractm : — Cuphea. 
The above names are ehiefly those of ornamental 
shrubs, garden plants, and common weeds. We have 
so far, no very serious reports of injury to any of 
our more important economic plants. It will be noticed 
that both the tea and the coffee plant figure on the 
list. Of the latter 1 have seen abiudoned plants in 
waste land thickly colonized by the bug. Superin- 
tendents of coffee estates should be on their guard 
against the introduction of this pest. 
The Tea plant fortunately does not appear to be 
a favourite food of the Orthezia, though, failing more 
favoured plants, it can subsist and breed on our 
staple product, and the subsequent generations mi^ht 
very readily acquire the taste for Ceylon tea. The 
danger arises from the enormous and rapid repro- 
ductive powers of the insect. When it finds a con- 
genial food plant— such as Lantana— it multiplies 
till every shoot is thickly tenanted, and the later 
broods are simply crowded off aud compelled to seek 
fresh p-istures. The several instances of the esta- 
bhshment of the pest upon tea have manifestly 
arisen in this manner. 
EEMEDIAL ITEASCKES. 
The Orthezia is one of, if not the most resistent 
of all scale-bngs towards insecticides. It is therefore 
a useful subject upon which to test various treatments 
An insecticide that will kill Orthezia can be almost 
guaranteed against any scale pest. It is remarkable 
that the half-grown insects will often survive treat- 
ment that has successfully destroyed the younger 
and older individuals. 
In the case of isolated trees attacked by this ceit 
the gas treatment is really the most effective ' and 
complete. This consists in covering the tree with a 
tent or sheet of some closely woven material be- 
neath which hydrocyanic acid gas is generated The 
deadly gas will penetrate to every part of the tree 
and reach every single insect. I have recently as- 
certained by experiment that an extra strength of 
the gas with a shorter exposure (than usually pre- 
cribed) is the most certainly fatal to the insects 
