294 INSECTS 



tree trunks it prevents the setting of young scales. A 

 continuous coat of whitewash will absolutely prevent 

 the setting of all scales and will keep many of them 

 from hatching; but it requires rather a thick coating to 

 effect this, for the lifting of the scales when the young 

 are ready to emerge, will usually break the coating. 

 In chicken-houses the wash should be applied with a 

 spray pump so as to force it into cracks and crevices, 

 and the addition of a little carbolic acid is here a dis- 

 tinct gain to the wash. The same may be said of it in 

 stables and out-buildings generally. Instead of the 

 crude carbolic acid, which is not readily soluble or mis- 

 cible with watery liquids, one of the many soluble tar 

 or cresol preparations may be used in liberal quantities. 

 Tree trunks are often white-washed to prevent borers 

 from entering, and with good effect so long as the 

 coating is thick and well put on. But the egg-laying 

 instinct is among the strongest, and the parent beetles 

 of round, flat-headed and bark borers will hunt for a 

 broken point, an unfilled crevice or a loosened bark 

 scale, to find a place where they can safely deposit an 

 egg, while the clear-wing moths will lay their eggs 

 anyway, and trust the minute caterpillar to find a bare 

 place or a crevice through which entrance may be 

 obtained to the sap-wood below. 



On foHage, whitewash is not an advisable apphca- 

 tion; its brittle character makes it quickly imperfect, 

 even where the tissue itself is not harmed. 



In its dry condition the range of usefulness of lime 

 is much greater. Air-slacked lime mixed with Paris 

 green for application through a blower or powder bel- 

 lows is well known, and as a driver in fields of cucurbs 

 invaded by the cucumber beetles, it is relied upon in 

 many parts of the country. As a dry hydrate, that is 

 slacked with just enough water to crumble it into a dry 



