when the undrained pools upon his land breed mosquitoes that 

 range the neighborhood. 



An insect whose life-cycle excellently illustrates this necessity 

 for community labor is the peach-tree borer. The adult of this 

 pest is a pretty little moth, the females having bluish wings and an 

 orange band on the abdomen, the males having clear wings and 

 no orange band. The eggs are laid on the bark of peach trees, 

 near the ground. W'hen highly magnified they show beautiful 

 reticulate markings, as do the eggs of many insects. The larvae 

 or "grubs" bore into the bark, and throughout the wood, forming 

 long winding tunnels, and greatly injuring or killing the tree. 

 When mature the grub forms a cocoon near the surface of the 

 ground, and changes into the pupa from which the adult emerges. 

 Trees infested by these borers can be recognized by the large 

 masses of gummy exudation around the base of the tree. 



There are various devices for protecting the trees from the 

 attacks of this pest. Coverings of tarred paper, wire and wood- 

 veneer have been tried with varying success, the idea being to pre- 

 vent the female from la}'ing eggs on the tree. In an experimental 

 orchard it was found that deterrent sprays sometimes kill the 

 trees. 



Fighting the peach-tree borer means, then, that all persons own- 

 ing peach trees must enter into the campaign. Otherwise a single 

 unguarded tree may supply a large region. 



The cabbage-worms also illustrate the need for "team work." 

 The white butterflies are well known to every countryman. The 

 eggs are laid on the cabbage leaves. These are delicately sculp- 

 tured. The larvae devote their entire time and energy to the 

 devouring of cabbage foliage, and if they are numerous the cab- 

 bage naturally succumbs. I'ortunately the caterpillars are sub- 

 ject to the attacks of a fatal bacterial disease, which aids in hold- 

 ing them in check. They have also a number of parasitic enemies, 

 who decimate their ranks. When mature the caterpillar suspends 

 itself by means of a silken button and girdle and transforms to a 

 protectively colored and quiescent chrysalis, from which emerges 

 the adult. To eradicate the cabbage-worms of a given region 

 obviously demands the cociperation of all the cabbage growers of 

 that region, else a single untended patch will become the breeding 

 grounds for the whole region. 



Man is aided in his combat against ilestructive insects by the 

 fact that many insects are predaccous, feeding upon other insects. 

 Dragon flies, which feed upon mosquitoes, and mud-wasps, which 

 fill their nests with spiders, are well known examjilcs of this class. 

 l'erhai)s C)nc of the most remarkable of these predaccous insects 

 is the ])raying mantis. 'J1iis strange creature is so-called because 

 of its hyj)()critical altitude of ])i<)us harmlessncss, the highly spe- 

 cialized front legs being, in reality. i)owcrful grasping organs, 

 whercwitii the wolf in sheei)'s clothing seizes its helpless prey. 

 Ihe eggs are laid in ciu'ious masses, wliose tops have the appear- 



