98^ THE GYPSY MOTH. 



times scatter to a considerable distance. Though this is the 

 rule there are some exceptions. In some localities, presum- 

 ably where the larvae are persecuted by many enemies, they 

 are found scattered abroad over a considerable area even 

 when food is abundant. 



The moths are sometimes distributed by birds. Many 

 birds feed upon the caterpillars, and in some cases they have 

 been known to drop them alive while carrying them to their 

 young. As the larvse are very hardy and are likely to 

 survive rough treatment, they may be scattered somewhat 

 in this way. Some of the distribution in woodlands may 

 be thus accounted for. The smaller larvae may even be 

 occasionally carried a short distance on the feathers of a 

 bird. The caterpillars are also occasionally transported 

 by the wind. As they hang by threads from the trees 

 they are sometimes swept off by sudden gusts of wind and 

 carried to a distance of perhaps a hundred yards. As the 

 moths are found distributed along running streams, it is 

 probable that caterpillars and imagoes are occasionally swept 

 down stream, and that now and then an egg-cluster is car- 

 ried away on a floating piece of bark or dead twig or branch. 

 Pieces of driftwood with eggs upon them have been found 

 on the banks of streams and on the shores of islands in 

 ponds. Egg-clusters thus exposed to the action of water 

 have been known to hatch. The moth has been distributed 

 in the same way along tide-water streams and even to trees 

 and bushes growing on spots above the level of tide-water 

 in salt marsh. Wherever the insect is numerous the eggs 

 are sometimes laid on the leaves of the trees. They are fre- 

 quently laid on dead leaves on the ground. In either case 

 the leaves may be afterwards blown to some distance by the 

 autumnal winds. Egg-clusters may be broken during gales 

 by the branches of a tree beating against each other or the 

 trunk, and the scattered eggs will then be blown away by 

 the wind. Other ways in which distribution might happen 

 will occur to those familiar with the subject. But the pe- 

 culiar distribution of the moth over a region more than two 

 hundred square miles in extent cannot be accounted for 

 either by the movements of the caterpillars or by any of the 

 foregoing causes, for there are 'well-marked isolated colonies 



