280 THE SUGAR BEET- 



to compress the soil, thus preventing the butterfly 

 from coming to the surface as soon as the metamor- 

 phosis is complete. We consider the best plan of all 

 for America, where wood is cheap, is to make large 

 fires on the neighboring hills; the ^N^octuas for miles 

 will come to the light at once and be burned. The 

 other insects of this class have similar habits, the dif- 

 ference being their color, which becomes more and 

 more beautiful, for those accustomed to fly during a 

 certain portion of the day. 



Then, again, these caterpillars' tastes seem to vary, 

 some preferring the top of the beet to the leaves. In 

 this case we consider there is even more harm done 

 than when the latter alone are attacked, as from the 

 crevices made by these insects small roots will grow, 

 thus diminishing the quantity of sugar. 



The last insect known to us of the group of Lepi- 

 dotera is the Hadena hassicce. We are not familiar 

 with its habits, but are informed that it frequently 

 does considerable harm. 



We will now speak of a class of insects belonging 

 to the group called Diptera. Unfortunately the ento- 

 mologists have not given sufficient attention to this 

 portion of their science, and consequently but little is 

 known regarding their habits, a knowledge of which 

 is necessary for their destruction. 



The most important of these insects, a sort of fly 

 (see fig. 73), having wings which are slightly yellow, 

 and which is called Phyto7nyzides, belonging to the 



