460 



COLEOPTERA. 



effected by extending the prothorax so as to bring the proster- 

 nal spine to the anterior part of the mesosternal eavit}' , then 

 suddenly relaxing the muscles so that the spine descends 

 violently into the cavity, the force given by this sudden move- 

 ment causes the base of the elytra to strike the supporting 

 surface, and by their elasticity the whole body is propelled 

 upward." 



The larvae, known by the name of Wire-worms, are vegetable 

 feeders, living on the roots of grass, wheat, corn, potatoes, 

 turnips and other garden vegetables. Fig. 419 (enlarged 

 four times) represents a larva of this family found by 

 Mr. Sanborn in the roots of the squash vine. The eggs 

 are laid probably in pastures and fallen ground where 

 the surface is undisturbed, or in the vicinity of rotten 

 wood. The larvae moult three times, and some species 

 are known to live in this state five years. AVhen fully 

 grown they transform in an earthen cocoon, and may 

 lie seen rising out of the ground during the summer, 

 9- especially in June. The larvae are very long cylin- 

 drical (whence their name wire-worm), hard -bodied and diffi- 

 cult to kill, and are generally pale testaceous, or yellowish red 

 in color. They have onl^' six thoracic legs, and a slight anal 

 prop-leg ; the body is flattened towards the head and tail. 



Eucnemis differs from the true Elaters in the serrate an- 

 tennas being inserted in approximate grooves at the margin of 

 the thorax beneath, which makes the clypeus narrow. The 

 species do not leap so vigorously as those of 

 other leaping genera. Fornax differs from 

 Eucnemis in the antennoe being filiform. 

 In AcMocera (Fig. 420, A. obtecta Say) the 

 third joint of the antennas is equal to, or 

 larger than the fourth. In Elater and its 

 allies, the antennse are widely separated, 

 being inserted in small cavities (fovese) 

 under the margin of the front, and before 

 the eyes. Alans ocidatus Esch. is the largest 

 Elater we have, the scutellum is oval, and the elytra have a 

 broad margin. The genus Elater has the front of the head 

 convex and margined quite broadly, and the thorax is always 





Fig. 420. 



