OF THE FARM AI^D GAEDEI^-. 



103 



coYers so thoroughly dilated at the sides into a broad and 

 flat margin, as to forcibly recall the appearance of a tur- 

 tle, whence the jDoj^ular name. Many haye the singular 

 power, in a greater or less degree, of changing their color 

 when alive, some of them shine at will with the most 

 brilliant metalhc tints. 



Insects, like the higher animals, are usually cleanly in 

 voiding their excrement, but the larvae of several species 

 of beetle have the peculiar habit of covering themselves 

 with their own excrement. The larvaB of the Three-lined 

 Leaf-beetle (Lema trilineata, Oliv.), which sometimes 

 proves injurious to the potato in the East, has this habit, 

 as do several others. 



But the larvae of the Tortoise-beetles are imr excellence 

 the true dung-carriers. In the instances related above, 

 the load is carried immediately on the back, but our Tor- 

 toise-beetles are altogether more refined in their tastes, 

 and do not allow the dung to rest on the body, but simply 

 shade themselves with a sort of stercoraceous parasol. 



The larvae of all the species that have been observed are 

 broad and flattened like the beetles, and have the margins 

 of the body furnished with spines which are often 

 barbed (fig. 75). Usually there are thirty-two of these 

 spines, or sixteen on each side of the body. Four of these 

 are situated on the prothorax, which forms two anterior 

 projections beyond the common margin; four of them — 

 the two anterior ones longer than the others — are on each 

 of the two following thoracic segments, and each of the 

 abdominal segments is furnished with but two. There 

 are nine elevated spiracles each side superiorly, namely, 

 one immediately behind the prothorax and eight on the 

 abdominal segments. The fore part of the body is pro- 

 jected shield-like over the head, which is retractile and 

 small. 



The eggs from which these larvae hatch, and which we 

 do not recollect to have seen anywhere described, are de- 



