LITTLE AIR POLICEMEN 247 
little egg-laying tools for the purpose of deposit¬ 
ing their eggs in the tissue of plants. Others 
lash the water with their abdomen, thus allowing 
the eggs to be washed off. Certain species choose 
pond sites for their nursery, others prefer small 
streams, and still others like the swift running 
water. The dragon-fly nymphs are often called 
water tigers, because of their voraciousness. As 
a clan, the dragon-flies belong to the Odonata, or 
membranous-winged order. Their nearest of kin 
are the May-flies, white ants, old Madam Doodle¬ 
bug, 1 and the little lace-winged flies. 
“ Because of their habit of swarming and mi¬ 
grating in immense numbers, in times gone by, 
the dragon-fly was the subject of no little super¬ 
stitious dread. The folk-lore of Europe and the 
Orient abounds with strange tales of these fierce- 
looking insects,—the Devil's own darning nee¬ 
dles. According to the annals of Illinois, one 
day in August, 1881, the air for miles around was 
literally alive with dragon-flies, swirling from a 
foot above ground to as high as the eye could 
reach. They followed a southwesterly course, 
and were bound who could say whither, and with 
what evil portent? Naturalists are now satisfied 
that dragon-flies migrate only when forced to do 
so by the drying up of the ponds and streams 
where they have made their homes. To-day the 
