368 



PROTECTION AGAINST INSECTS. 



coating on branches and twigs of 5- to 15- years-old spruce, 

 which makes them languish for 

 several years. It has done much 

 damage to spruce plantations in 

 Saxony, and near Tharand was found 

 on mature spruce, which had been 

 injured by locomotive smoke. This 

 insect is attacked by a parasitic weevil 

 (Brachy tarsus varius, Fabr.). Leca- 

 niumfraxini, Sign., attacks ash. 



Another injurious genus of scale- 

 insects is Aspidiotus, in which the ? 

 live under a coat formed of larval 

 skins and a waxy scale, the $ under a 

 smaller waxy scale and one larval skin. 



Aspidiotus salicis, L., attacks pop- 

 lars, willows and ash, and frequently 

 kills black poplar. When crushed, a 

 blood-red fluid exudes from the insects. 

 This species greatly impairs the growth of young ash. 



Fig. 191. Spruce - shoot 

 attacked by Lecanium hemi- 

 cryphum, Dalm. (Natural 

 size.} 

 a Feeding scale-insects. 



D. Orthoptera. 

 FAMILY I. GRYLLIDAE (CRICKETS). 



Description of Family. 



The insects of this family possess a thick, free head, with 

 long bristly antennae of many joints, and 2 or 3 ocelli ; hind- 

 wings folded longitudinally, and projecting beyond the wing- 

 cases, but often aborted, or absent, not roof-shaped in repose. 

 Body cylindrical ; fore-legs formed for burrowing ; tarsi 

 3-jointed. Ovipositor long, sometimes absent. The species 

 produce a chirping noise by rubbing the wing-cases together. 



They dig holes in the ground, and live partly on larvae and 

 worms, partly on the roots, seeds and fruit of forest plants, or 

 on grass and herbage. 



1. Gryllotalpa vulgaris, Latr. (Common Mole-cricket). 



a. Description. 



Imago 35 to 45 mm. long, reddish-brown or dark brown, and 

 lighter beneath ; the wing-cases short with black veins, not 



