566 
THE TROPICAL AGRICULTURIST. 
[Feb. 2, 190S. 
unwilling visitor. In this diagram I have endeavoured 
to shew a section of one of the pitfalls. And here is 
a photograph of the insect removed from its den. If 
we examine the weapons with which it is provided, 
we find that each curved jaw is composed of two 
parts— the mandible and the maxilla— one of which 
slides in a groove cut in the face of the other. The 
two parts combine to form a tube through which the 
juice of the victim are absorbed. When fully grown 
the larva constructs a globular cocoon of sand 
and eventually emerges in the form here shown. 
It looks rather like a small dragon-fly, but the 
body is shorter in comparison to the length of 
wing, and it has clubbed antennae which are not 
seen in the true dragon-fly. The perfect insect 
may often be seen flying feebly round the lamp at 
night, or resting — in the daytime— on the verandah 
walls. An allied insect with similarly constructed 
jaws is 
THE " APHIS-LION " 
B, name given to the larvae of the lacewicg flies 
(Chrysops and Hemerobia). This larva— as you may 
see from its picture— covers its body with the empty 
skins of its victims, and walks about— a veritable 
" wolf in sheep's clothing" ; though its covering is 
really more for protective than aggressive purposes, 
for its victims— the Aphides— are sluggish insects and 
quite incapable of resisting or escaping from their 
rapacious enemy. Aphides— as you doubtless know- 
are the small green or brown plant-lice that crowd 
upon the young shoots of roses and many other plants. 
The Aphis-lion calmly establishes itself on the edge 
of the crowd, picks np Aphis after Aphis, sucks it 
dry and neatly, adds its empty skin to the trophy of 
scalps carried on its back. These habits, though unplea- 
sant for the aphis, are of great service to the agricul- 
turist. I have here a photograph of the little animal— 
un-robed. Mosquitoes are not usually looked upon as 
friends of man. But we have one species— the largest and 
most brilliantly coloured representative of the family 
in Ceylon— that may fairly claim that title ; for its 
larva is carnivorous and feeds entirely upon other 
mosquito larvae. Its scientific name is Toxorhjnchi- 
tes immisericors. It is common in the Peradeniya 
Gardens, where it particularly frequents the clumps 
of Giant Bamboo. 1 have recently been studying its 
life history— which was hitherto unknown. It breeds 
in the water that accumulates in the hollow stumps 
of the bamboo. Though it is popularly termed the 
' elephant mosquito,' I think that title must have been 
gained more on account of its comparatively large 
size than from its ferocity. I have never been 
bitten by one myself, and have met only one person 
who professes to have experienced the bite of this 
species. In the adult stage, it feeds principally on 
fruit, lhave kept specimens alive in captivity and 
have' watched them sucking the juice of plantains. I 
have freely offered them my arm on the chance of 
their wanting a change of diet, but they have never 
availed themselves of my kindoess, though other cap- 
tive mosquitoes have not been so forbearing. The 
carnivorous larva of this species carries a remarkable 
raptorial organ on its head.j^T^ ^^-p^^^va of the 
common mosquitoea^^jjj Mentis is i>.r"eles, there is 
a pair of brush-lmS, „jggQ p.- .ne iront of the head 
which— by a rapid lasifing movement— create a current 
in the water which brings the suspended food to their 
mouths. They are termed " whorl organs." In the 
larva of our Toxorhjncldtes these delicate whorl organs 
are replaced by two groups of sharp curved hooks, 
opposing each other. With this apparatus it seizes the 
smaller larvae of other mosquitoes when they incau- 
tiously approach within rep.eh, and holds them firmly 
while they are being devoured. It is a sluggish insect 
and progresses through the water with difficulty by a 
series of awkward contortions. But it does not require 
any great activity. There is a super-abundance of 
this commodity on the part of its prey : for the other 
mosquito larvae are constantly jerking themselves 
about in the water, and— in the confined space of a 
bamboo stump— are sure, sooner or later, to run up 
against the apparently torpid larva of Toxorlujnchites, 
In an instant the hooks — which ordinarily lie back 
on each side of the head — are closed upon the victim. 
It seldom misses its stroke. 
IN THE ANT TEIBE 
we have an example of predatory insects 
that hunt in packs. They might be called 
the wolves of the insect world. The fierce 
" Eed Ant" ((Ecophylla smaragdina) scours the 
country in the neighbourhood of its nests, comn*uni- 
cating with its fellows by means that we ao not 
properly understand. With their strong jaws they can 
overpower quite large caterpillars and other soft-bodied 
insects. I have recently had bitter experience of the 
rapacity of another large ant (3Ii/rimcaria svbearinata), 
when a horde of these insects found their way into 
one of my breeding cages and tore to pieces a number 
of full-grown silk worms. There is a comparatively 
small but very active reddish ant, named Plagio- 
lepis gracilipes, whose acquaintance you may often 
have made in your sugar basins. Though decidedly 
fond of sweets, this species is really very useful in 
the house, for they are the sworn foes of cockroaches. 
I have on several occasions watched a cockroach-hunt 
conducted by these ants. The cockroach, as it hurries 
across the floor in search of cover, is surrounded by a 
cloud of skirmishers. They never attempt to grip 
their quarry. Their aim appears to be t,o dash in and 
give a quick bite at the sensitive antennae of the 
cockroach and dart back again. They must secrete 
some very subtle poison, for after one or two tiny 
wounds, the cockroach turns over on its back in a 
paralysed condition, when the skirmishers close in and 
drag away their victim to their nest. This sugar anc 
is remarkable for its ability to overcome more foimid- 
able species of the same tribe, though unprovided 
with any apparent weapon of offence. Its jaws are 
small and weak, as you can see from this enlarged 
photograph of its head. Yet it defeats, in single 
combat, the ferocious Red Ant whose jaws 
are powerful enough to cut it in half at a 
single stroke. It pursues the same tactics just 
noticed in the description of the .cockroach -hunt. 
Some ants make their hunting excursions in orderly 
array, like an army, and apparently have recognised 
signs or words of command — imperceptible to our 
senses. Of this type is that elongate shining-black 
ant (Lobopelta species) which is possessed of a power- 
ful sting. I was once watching an army of these ants. 
They were travelling in column — some 4 or 5 deep. 
Suddenly the leading files halted; the rest of the 
column closed up, till they were all packed together 
in a dense mass — one above the other. When the 
last straggler was in his place, the secret signal was 
given, and a combined dash was made to a large 
fallen leaf lying in the drain. I had seen nothing 
suspicious about this leaf. But doubtless one of the 
scouts of the black army had brought word that a 
large and succulent worm was concealed beneath it. 
As soon as it found itself discovered, the worm — 
which was of a slippery and active sort — commenced 
a violent series of jerks and twists in its endeavour 
to escape. But soon its entire surface was hidden 
beneath the thickly clustering ants, and a hundred 
stings had been plunged into its body. In less time 
than it has taken me to describe the episode, a 
procession had been formed and the limp corpse of 
the worm was being conveyed back to head quarters. 
But if I were to attempt to describe the remarkable 
habits of ants in general, I should be wandering from 
my proper subject, and I should keep yon here all 
night. My allotted time and your patience must 
both be exhausted. The ways of ants would form 
a sufficient subject for a separate lecture. 
It only remains for me now to thank you for the 
kind patience with which yon have listened to my 
somewhat discursive remjirks upon predatory insects. 
