FOR YOUNG READERS

Press, Volume LXXVII, Issue 23315, 29 April 1941, Page 4

FOR YOUNG READERS

* NATURE NOTES RAT-TAILED MAGGOTS IBy L. W. McCASKILL,] Roy Hydes, of the school at Ashburton Forks, has sent an excellent description of “some most peculiar grubs which the pupils found in a tin of liquid manure in the school ground.” These strange insects, usually found in liquid manure barrels but also in stagnant pools and disused sheep-dips, are known as rat-tailed larvae or maggots. When 'fully grown they may be an inch long, with seven pairs of hooked stumps on the lower side. The body is cigar-shaped, soft to the touch, and grey in colour. Rising from the hind end is a “tail.” This is really a breathing siphon with a most complicated structure which enables it to be extended or reduced in length very rapidly. The narrow tip can be pushed in or out of the lower part; this again can also be contracted. If one of these maggots is kept in a jar of water, it will lengthen or contract the tail according to the depth of the body below the surface. At one instant the tail may be only half an inch long; a few seconds later it may have extended to as much as three inches. The maggot cannot breathe dissolved air as other aquatic larvae can, so it has developed this elaborate piece of apparatus to enable it to live in the liquid filth on which it feeds and yet obtain atmospheric air by poking the tip of the tail above the surface. Inside the telescopic tail are two air tubes which lead down to air tubes branching through the body of the insect. At the tip are some hairs or bristles which are spread out on top of the surface film. These seem to keep the mouths of the air tubes open and help suspend the insect from the surface. When fully grown the maggot leaves the water and crawls into damp earth to pupate. The body and tail shorten, two new breathing tubes grow out of the chest, region, and the skin becomes brown and hard. In about 10 days, if it is the summer brood, the adult insect emerges. If it is the autumn brood the pupa will lie motionless in the ground over the winter and the adult will emerge in early summer. Adult Bcsembles Drone Bee The adult looks much like a drone bee. Actually it is a fly and because of this resemblance is well named the drone-fly (Eristalis tenax). It is a real lover of the sun and may> usually be found on flowers in full sun sucking up nectar with its tube-like proboscis. It differs mainly frOm the bee in that, like all true flies, it has only one pair of wings—bees have two pairs. Another difference is that it has no sting though it may be seen twitching the abdomen constantly in the manner of a bee preparing to sting. So. close is it in habits and appearance to a real bee that even spiders are known deceived and treat a captured drone-fly with the care normally reserved, for bees. . • • ■... t As a schoolboy struggling to learn Latin, I had to translate “recipe for bees.” He said that if you took the body of an ox, battered it about, and then enclosed it in a suitable chamber, a swarm of bees would eventually arise from it. Virgil may have been repeating a very ancient legend or he may have seen drone-flies rising from a car-' case and mistaken them for bees. At least 3000 years ago people in Egvpt believed that from the decomposing body of an ox a swarm of bees would arise by “spontaneous generation.” From the life history described above we can see how the ancients were mistaken. As the body began to decay, the liquid filth resulting provided an ideal place for a drone-fly to lay her eggs. The maggots would develop, pupate, and finally emerge as adult,

flies. These, because of careless observation, would be mistaken for a swarm of bees.