ORTHOPTERA 391 



boscis. Their last tarsal joints are modified into large hooks, by which 

 the parasite attaches itself to the hairs of its host. 



The Head Louse (Pediculus capitis) lives on the heads of dirty 

 people, gluing its eggs (nits) on to the hair. 



The Clothes Louse (P. vestimenti), on the other hand, deposits its 

 eggs between the seams of garments, and sucks blood from the less 

 hairy parts of the body. 



The Dog Lice (Trichodectes), which consume the hairs of dogs and 

 other mammals, and the Bird Lice (Philopterus), which feed on the 

 barbs of birds' feathers, are also classed with this division, although, on 

 account of the hard nature of their food, their mouth parts are adapted 

 for biting (masticatory). 



ORDER VII. : STRAIGHT-WINGS (ORTHOPTERA). 



Mouth parts masticatory ; first thoracic segment (prothorax) free ; fore- 

 wings forming wing-covers, hind-wings membranous, folded longitudi- 

 nally in fan fashion. Metamorphosis incomplete. 



Group 1 : Leaping Orthoptera (Saltatoria) . 



The Great Green Grasshopper (Locusta viridissima) . 



(Length about 1£ inches.) 



A loud and many-voiced concert resounds in autumn on fields and 

 meadows. The musicians are insects, among which the grasshoppers 

 take a specially prominent place. (Name other musical insects.) The 

 loud " tchick-tchick " resounding from yonder turnip-field, or from the 

 bushes and trees which skirt the field, is the "song" of a grasshopper 

 species — the green grasshopper, with which everyone is familiar. 



A. Colour. 



Let us very carefully approach our songster, so that it may not 

 observe us. This, however, is easier said than done, for, though we hear 

 it, we cannot discover its exact whereabouts. Nor at last, when we have 

 sighted the creature, do we wonder at having had to search so long ; for 

 its grass-green colour completely hides it among the leaves which form 

 its favourite resort (hence called green grasshopper). This green colour 

 is, of twofold use to the insects, serving both as a protection against 

 enemies and as a means of hiding its presence from its prey (see 

 Section 0). 



