No unusual sound, so far, had disturbed the stillness of the night.  Save for the muffled throb of the rare all-night cars passing the front of the house, our vigil had been a silent one.  The full moon had painted about the floor weird shadows of the clustering ivy, spreading the design gradually from the door, across the room, past the little table where the envelope lay, and finally to the foot of the bed.

The distant clock struck a quarter-past two.

A slight breeze stirred the ivy, and a new shadow added itself to the extreme edge of the moon’s design.

Something rose, inch by inch, above the sill of the westerly window.  I could see only its shadow, but a sharp, sibilant breath from Smith told me that he, from his post, could see the cause of the shadow.

Every nerve in my body seemed to be strung tensely.  I was icy cold, expectant, and prepared for whatever horror was upon us.

The shadow became stationary.  The dacoit was studying the interior of the room.

Then it suddenly lengthened, and, craning my head to the left, I saw a lithe, black-clad form, surmounted by a Yellow face, sketchy in the moonlight, pressed against the window-panes!

One thin, brown hand appeared over the edge of the lowered sash, which it grasped—­and then another.  The man made absolutely no sound whatever.  The second hand disappeared—­and reappeared.  It held a small, square box.  There was a very faint click.

The dacoit swung himself below the window with the agility of an ape, as, with a dull, muffled thud, something dropped upon the carpet!

“Stand still, for your life!” came Smith’s voice, high-pitched.

A beam of white leaped out across the room and played full upon the coffee-table in the center.

Prepared as I was for something horrible, I know that I paled at sight of the thing that was running round the edge of the envelope.

It was an insect, full six inches long, and of a vivid, venomous, red color!  It had something of the appearance of a great ant, with its long, quivering antennae and its febrile, horrible vitality; but it was proportionately longer of body and smaller of head, and had numberless rapidly moving legs.  In short, it was a giant centipede, apparently of the scolopendra group, but of a form quite new to me.

These things I realized in one breathless instant; in the next—­ Smith had dashed the thing’s poisonous life out with one straight, true blow of the golf club!

I leaped to the window and threw it widely open, feeling a silk thread brush my hand as I did so.  A black shape was dropping, with incredible agility from branch to branch of the ivy, and, without once offering a mark for a revolver-shot, it merged into the shadows beneath the trees of the garden.  As I turned and switched on the light Nayland Smith dropped limply into a chair, leaning his head upon his hands.  Even that grim courage had been tried sorely.