142 



AA^ ECONOMIC ENTOMOLOGY. 



Fig. 104. 



song may be heard at all periods of the day and until late into 

 the night, from the end of May to nearly the end of June, louder 

 and more intense on warm or hot days. No injury is done by 

 the insects in feeding, but their egg-laying habits often cause 



considerable trouble. Though 

 the larvs feed under ground, the 

 eggs are laid in the twigs and 

 branches of trees ; a series of slits 

 being cut by the powerful ovi- 

 positor of the female, forming 

 smooth chambers in w^hich the 

 eggs are arranged in series. 

 There is nothing to be done when 

 such a brood occurs except take 

 the injury and make the best of 

 it. Of course valuable plants or 

 trees can be protected by mos- 

 quito-netting, but my statement 

 applies to ordinary farm and or- 

 chard crops. The fact that we 

 know when the insects are to 

 appear makes it possible for the 

 fruit-grower to guard himself to 

 some extent by not setting out 

 voun^ stock. On old trees no 

 serious injury will be done, and 

 if no pruning is attempted during 

 the winter preceding, the insects 

 will probably find an abundance 

 of useless twigs to oviposit in. 

 Young trees, however, are some- 

 times so injured as to make them 

 practically useless, either by com- 

 pletely spoiling the shape, or by 

 so weakening the main branches 

 that they never become strong enough to bear a proper top. 

 Wherever the English sparrow has been introduced, the period- 

 ical cicada is doomed. These birds seem to have an intense 

 hatred for the insects, attacking and pulling them to pieces in 



6 



a: 



Cicada egg-punctures : at a, freshly 

 made ; at 3, old and distended. 



