ANOPLURA. 135 



but somewhat parallel wavy rows. It requires a 

 good microscope and a high power to show them dis- 

 tinctly, and they should appear perfectly black and 

 separate. The little lines are much coarser in some 

 scales than in others; so that there are easy and difficult 

 scales, as they are called. 



The Podura may be caught by holding a sheet of 

 paper near their haunts and disturbing them; and 

 when they have jumped upon the paper, a slide laid 

 upon them and gently pressed will remove some of 

 the scales for examination. 



The scales should be mounted as dry transparent 

 objects ; for if wetted, they become very transparent, 

 and the markings appear removed, which however is 

 not really the case. 



The scales of Lepisma saccharma (PI. X. fig. 19 d), 

 a member of this Order, were formerly used as test- 

 objects ; but they are too easily made out to serve 

 for this purpose with modern microscopes. The in- 

 sect is not common. The scales (fig. 19 d] exhibit 

 continuous nearly parallel longitudinal lines or ribs. 



ANOPL<JRA (avoTrXo?, unarmed, oupa, tail). This 

 third Order of insects consists of the Lice of the Mam- 

 malia and birds. They are minute, resembling mites 

 to the naked eye, but may be at once distinguished 

 from them by the distinct head and thorax and the 

 presence of six instead of eight legs. 



Some of them are suctorial, i. e. have a short and 

 slender tube, with which they suck the blood of the 

 animals of which they are parasites ; while others are 

 mandibulate, or have mandibles, and also maxillae, 

 their food consisting of portions of feathers, hairs, 

 and scurf. The legs are usually short and stout, and 

 the claws large and powerful, to enable them to hold 

 firmly to the hairs, &c. The Anoplura are most 

 abundant on dirty and diseased animals. 



SUCTOR'IA. The fourth Order of insects consists of 

 the genus Pulex, Pulex irritans being the human 



