35 6 UTILITARIAN ZOOLOGY 



(Athalia spinarum], Apple Saw- Fly (Hotlocampa testudinea), 

 Gooseberry and Currant Saw- Fly (Nematus ribesii], Cherry and 

 Pear Saw- Fly (Eriocampa limacina), Plum Saw- Fly (Hoplocampa 

 fulvicornis), and Pine Saw-Fly (Lophyrus pini, fig. 1254). 



Other net-winged insects may at times be injurious, e.g. Wasps 

 sometimes damage large quantities of fruits, while Ants make raids 

 on provisions (especially those containing sugar), and Carpenter- 

 Bees (Xylocopa) destroy woodwork. 



Injurious Net-winged Insects (N europtera). The Biting- Lice 

 (Mallophaga) live as ectoparasites on birds or mammals, and feed 

 on their feathers or hairs, at the same time causing much irritation. 

 Domestic fowls are pestered by no less than five species of these 

 insects, one (Menopon palliduni) being particularly common. The 



Fig. 1254. Pine Saw-Fly (Lopkyrus pint). On the branch to the left are two larvae, a cocoon, and an adult male; 

 on the right is an adult female, enlarged (actual size indicated by the line). 



Biting Dog- Louse (Trichodectes latus] not only torments its host, 

 but also harbours a stage in the life-history of a tape-worm which 

 lives when adult in the dog's intestine. 



In some of the hotter countries of the world Termites or 

 " White Ants " are very harmful to furniture and woodwork, on 

 account of their habit of excavating and feeding upon wood (see 

 p. 120). An interesting example is giving by Sharp (in The 

 Cambridge Natural History), who says: "A Termite (Termes 

 tenuis] was introduced in what manner is not certainly known 

 to the island of St. Helena, and committed such extensive 

 ravages there that Jamestown, the capital, was practically de- 

 stroyed, and new buildings had to be erected ". 



Injurious Straight-winged Insects (Orthoptera). Locusts have 

 been one of the scourges of mankind from the earliest times, 

 owing to their enormous fertility and the wholesale manner in 

 which they devour all sorts of vegetation (see vol. i, p. 382, and 

 vol. iii, p. 379). The species which migrate from place to place 

 in vast swarms are those which do most mischief. The follow- 

 ing quotation from Sharp (in The Cambridge Natural History) 



