74 



KNOWLEDGE. 



[March 1, 1897. 



her abdomen until the tip touches the ground ; next, the 

 points at the end of the ovipositor are brought together so 

 as to form one, which is driven into the sand, worked from 

 side to side, and withdrawn, bringing with it a small amount 

 of sand. It is again extended, and the trowel-shaped organs 

 at each side of the tip are pressed deeper into the sand, 

 until the hole is three-sixteenths of an inch deep by one- 

 sixteenth diameter ; the ovipositor is then carefully with- 

 drawn, leaving the hole quite clear of loose sand. It is 



Fig. 1. — The Tiger Beetle {Cidiidela campesiris). 



again lowered to the full length, and an oval-shaped and 

 smooth egg, one-fiftieth of an inch long, is extruded and 

 placed at the bottom of the hole — "head up"; a few 

 largish grains of sand are put in, and the hole so artfully 

 concealed that few there be who find it. The beetle 

 immediately makes another burrow, frequently within half 

 an inch of the first, another egg is laid ; and so on until 

 quite a little colony is formed within a square foot. Each 

 female lays a large number of eggs, which hatch in a few 

 days into veritable little " tigers " of ferocity. 



During my sojourn at Woking I had fine opportunities 

 for studying these larvse, my first acquaintance with 

 which I made one bright day in May, when crossing over 

 a part of the common. My eyes were arrested by the 

 sudden appearance of a number of holes in the ground ; 

 their appearance was so sudden that I immediately puUed 

 up and stood perfectly still, when in a few minutes each 

 hole was filled up almost level — with something whose 

 exact nature I could not at once decide. I moved 

 forward a few inches, when every hole became empty — the 

 " something" had shot down out of sight. Once more they 

 filled up, and then I saw that it was a strange-looking head 

 of some insect. Drawing from my pocket a long, narrow 

 "fern spud," I drew my arm well back, and waited for 

 the head to reappear. On it coming up and settling down 

 with open jaws, I suddenly lunged out with my spud, 

 intending to strike across the vertical hole and cut off the 

 retreat of the creature. In this I was more than successful, 

 for I managed to cut off its head, while the tail went on 

 behind. I next tried to dig some larvie up, and, after a 

 good deal of trouble, managed to turn one fine one out 

 upon the sand (Fig. 2). 



Accustomed as I had become to all sorts of larviB, I must 

 confess that never before had I seen such a strange-looking 

 one. It had an immense head, which appeared altogether 



too large for the chin, which was produced into an enor- 

 mous size. The forehead was sloping upwards to the crown, 

 which was overlapped by a large chitinous, semicircular, 

 thoracic plate, followed by two smaller ones. The eyes 

 were very small and cunning-looking, three in number on 

 each side of the head. The most striking feature was the 

 pair of curved and turned-up mandibles, which resembled a 

 pair of tusks or cow's horns. The movement of these was 

 exactly opposite to those of an ordinary larva, whose 

 mandibles close ventrally, whereas those of the tiger 

 beetle larva closed dorsally. Future examination showed 

 to me the marvellous adaptability of these organs to the 

 changed surroundings and life of the larva. The mature 

 beetle runs after — and if necessary flies after — its prey, 

 which is seized between the mandibles, which open 

 and close beneath the head ; but in the larva this is 

 reversed and the prey seized by the mandibles opening 

 above the mouth. The legs of the larva were long 

 and sprawling, the toes bifid, long, and pointed ; the 

 abdominal segments flaccid and white, each with a brown 

 dorsal patch and tubercles on each side and back, sur- 

 mounted by long and short spines. The fifth abdominal 

 segment caught my eye, for I saw that it was produced 

 dorsally into a huge hump, having at the apex two short 

 but powerful spines, with another pair in front, the bases 

 of which were close to those on the apex ; these were long 

 and curved towards the centre, the hooked points sharp 

 and drooping towards the fourth segment. The larva was 

 capable of raising these long spines until they stood out 

 wide apart, with the hooked points almost at right angles 

 to the abdomen, and if pressed against any soft sand they 

 would immediately penetrate it. I saw at a glance that 

 this complex segment was intended to play some very 

 important part in the economy of the larva. The anal 

 segment was also armed with quite a brush of stiff spines, 

 which I concluded were intended to assist the larva in 

 walking. Happening to touch the tail, the larva imme- 

 diately turned its head and thorax right over its back, and 

 seized that part between its mandibles ; then, after a 

 moment's pause, it let go and sprang to a distance of 

 twelve inches. I saw that in doing this trick it had 

 immense mobility of the neck and thoracic segments. 

 After I had thoroughly examined these movements I let 

 it go. 



Determined to see what went on below ground, I adopted 



Fio. L'.— Larva. 



my old plan used when watching the subterranean work 

 of Attjpus iiiceiis — the British representative of trapdoor 

 spiders. This was to obtain some plain glass jars of the 

 type used by confectioners ; these I filled with damp sand 

 to within an inch and a half of the top, then taking a piece 

 of cane a quarter of an inch in diameter, I carefully made a 

 hole three inches deep, close to the side of the glass, which 

 enabled me to see all that was going on. I next turned 

 into this hole a larva which was nearly full-fed — about an 



