Insects Injukious to the Potato and Appi^e. 577 



ern border of that State, as well as in Connecticut, Massa- 

 chusetts, New Jersey, Delaware, Maryland, and Virginia, and 

 in that same year reached the seaboard in several places ac- 

 cording to Riley, but not until 1875 did I know of its ap- 

 pearance in Vermont in the southwestern part of the State 

 and not till June, 1876, did it appear about Burlington. Thus 

 its eastward march has been at a rate of from fifty to 

 seventy miles a year. I should rather say its spread has 

 been at that rate, for we do not find a moving mass of in- 

 sects leaving one place and going to the next. "Where they 

 have once been there they are still. It seems to be only 

 the surplus that extends eastward, and they diminish prob- 

 ably not so much because of migrations as because of the 

 increase of natural enemies and of artificial means of des- 

 truction in the hands of farmers. Tliis beetle, fig. 4, d, is, as 

 many of you doubtless know, a short, thick beetle shaped like 

 our common rose beetles, or lady-bugs. It is about one-half 

 inch long and a little more than one-fourth of an inch 

 broad when the wings are closed. Along the back are ten 

 black lines on a yellow ground, and the thorax is yellow 

 dotted with about eighteen black dots in rather a peculiar 

 mjvnner. The under side of the beetle and legs are black. 

 It is a clumsy, sluggish insect though able to fly if need be. 

 Riley says that in the latitude of St. Louis it has three 

 broods a year, but these are not separated by any well- 

 defined limits, for, as the female deposits eggs at any time, 

 and as the eggs mature at different times, the insect may be 

 found in all stages all through the summer. It goes into 

 the groimd in the fall and remains there (in the larval state) 

 19 



