Potato Insects and their Control 171 



not only potatoes, but tomatoes, eggplants, tobacco and 

 peppers. 



"It was first brought to notice," says Geo, C. Butz, 

 "about the year 1856. In 1861 it was found in the potato 

 fields of the settlers of Kansas. In 1862 it was in Iowa, and 

 in 1862 it appeared in southwestern Wisconsin. It crossed 

 the Mississippi River into Illinois in 1864. It was in 

 Michigan and Indiana in 1867, Ohio in 1868 and Pennsyl- 

 vania in 1870. It moved eastward at the rate of about fifty 

 miles a year for a number of years, but later it traveled 

 more rapidly. It is reported to have reached the Atlantic 

 Coast about 1874, and Nova Scotia about 1882. When it 

 reached the Atlantic Coast, it had traveled 1500 miles in 

 sixteen years, and nearly 1000 miles more the next eight 

 years in its march to Nova Scotia." 



The mature beetle hibernates in winter in the ground 

 usually at a depth of eight to ten inches and begins to fly 

 early in the spring. As soon as the first leaves of the po- 

 tato appear above the ground, the beetles fly to them and 

 soon lay their reddish yellow or orange-colored eggs in 

 clusters on the under side of the leaves. In about a 

 week the young beetles or larvae appear and begin to 

 devour the foliage with great rapidity. The larvae 

 pass through four stages or instars and are mature in 

 sixteen to twenty-one days, according to the weather. 

 Then they go into the ground and transform into the pupa 

 or resting stage, in which they remain at least a week — 

 usually longer — before coming out as the adult beetles. 

 The egg-laying period lasts about thirty-five or forty days. 

 The minimum time for the life cycle is about four weeks. 

 The last brood of larvae which disappear into the soil 

 before severe frost pupate there, remaining in the ground 

 in the form of perfect insects until the following spring. 



