COLEOPTERA. 



547 



little variation in form ; but in this stage the shape of the 

 parts of the head and the last segment of the body often 

 furnish reliable specific characters (Figs. 658 and 659). 



In those species that we have bred it requires several 

 years for the larva to complete its growth. In these species 

 the full-grown larva changes to a pupa in the latter part of 

 the summer, in a little cell in the ground ; the pupa soon 

 afterwards changes to an adult ; but the adult remains in 

 the cell formed by the larva till the following spring. 



Although we tried an extensive series of experiments, 

 extending over several years, we were unable to find any 

 satisfactory way of destroying the larvae infesting field 

 crops. But we found that if the cells containing pupae or 

 recently-transformed adults were broken the insects per- 

 shed. We conclude, therefore, that much can be done 

 towards keeping these insects in check by fall-ploughing; 

 for in this way many of the cells containing pupae or young 

 adults would be broken. 



The Eyed Elater, Alaus oculatus (A'laus oc-u-Ia'tus). — 

 Although most of our click-beetles are of moderate size, we 

 have a few species that are large. The most common of 

 these is the Eyed Elater (El'a-ter). This 

 is the great pepper-and-salt-colored fellow 

 that has two large, black, velvety, eye- 

 like spots on the prothorax (Fig. 660). 

 These are not its eyes, however. The true 

 eyes are situated one on each side of the 

 head near the base of the antenna. This 

 insect varies greatly in size, some individ- 

 uals being not more than half as large as 

 others. The larger larvae are about two 

 and a half inches long, and nearly four 

 tenths of an inch wide across the middie 

 of the body. They live upon decaying 

 wood, and are often found in the trunks of old apple-trees. 



There is an Elater quite similar to the preceding that 



Fig. 660. 



