214 PROTECTION AGAINST INSECTS. 



the same manner as A. viridis. A. sex-ynttatus, Herbst, is 

 common in France, where it riddles the wood of old poplars. 



FAMILY III. ELATERIDAE (CLICK-BEETLES). 

 Description of Family. 



Imagos long and slender, hard, resembling those of the 

 former family in general appearance, but usually without 

 metallic lustre. Antennae filiform, generally serrate or pecti- 

 nate (<?), 11-jointed. Prothorax broad posteriorly, its hind- 

 angles produced and acute. Fore and middle coxae spheroidal, 

 legs short and rather weak, tarsi 5-jointed. Abdomen of 5 

 segments. When laid on their backs they are able to spring 

 up in the air with a clicking noise, alighting on their legs. 



Generation, 3 4 years; length of time in larval stage 

 probably dependent on supply of food, and lasting only three 

 years when they are well nourished. 



Larvae long and slender brownish-yellow grubs, termed 

 wire-worms, with horny, flat, dark heads. They are lighter 

 coloured below, and have 6 legs and a stump-like tubercle 

 serving as an additional leg on the last segment ; they 

 generally live underground, or in old rotten stumps. They 

 are omnivorous, devouring roots, rhizomes, seeds, fungi, 

 decomposing vegetable and animal matter, and even other 

 insects. They abound in newly broken-up pasture, or clover 

 land, and are most destructive to agricultural crops, and in 

 forestry to sowings in nurseries and in the forest of acorns, 

 beech-mast, maple or hornbeam, and many coniferous seeds, 

 and to the roots and bases of the stem of young coniferous 

 and broadleaved plants. 



Pupation underground in July. The beetles emerge a few 

 weeks later, and may be found on flowers, or under bark or 

 stones. Wire-worms are the larvae of beetles of the genera 

 Elater, Athous, Agriotcs, especially A . lineatus, which is the 

 chief offender, and of other Elateridtf*. 



The larvae of Dolopius marginatus, L., gnaw the roots of 

 young spruce and Scots pine, and thus do much injury in 

 nurseries and plantations. Agriotes lineatus, L., and A. ob- 

 scurus, Gyll, devour acorns, and also coniferous seeds; Athous 



