BUGS. 209 



and curiously marked with bands, stripes, or spots of red, orange, blue, or metallic 

 green shagreened, and besides with one or more antennal joints flattened, and the first 

 joint bent and spined, or with bodies invested with sharp spines in all directions. 

 These are but a few out of the great assemblage of forms which tenant parts of the 

 earth ; but we shall take a nearer view of still others as we consider the various groups 

 into which this great Order has been arranged. 



SUB-ORDER I. - - PARISITA. 



At the very lowest verge of the Order we are confronted by an assemblage of small 

 degraded insects which are the pests of man and animals. They are the haustellate 

 Lice that have been removed from the ill-defined group Aptera of Linnaeus, and are 

 now generally admitted to be Hemiptera of low grade. 



As there are only characters of unfixed rank to separate them from the lowest 

 Heteroptera such as Cimex lectularius, it is with difficulty that we follow Claus and 

 other systematists in assigning to them a position of subordinal value. Professor 

 Westwood has persistently retained them, together with the Mallophaga, which are 

 mandibulate, have a flat labium and other differential characters, in a separate order 

 styled Anoplura. But since he has himself recently described some forms which have 

 the labium built after the type of a genuine heteropterous rostrum, coincident with 

 an imperfect metamorphosis and general hemipterous structure, there is no longer 

 a satisfactory reason for placing them outside of the Hemiptera. Mr. McLachlan has 

 recently removed the bird-lice or Mallophaga to the Pseudoneuroptera, where they 

 rest in relationship with Termes and Psocus ; while the louse of the beaver has been 

 relegated by Dr. Leconte to the Coleoptera ; and the flea has long since been consigned 

 to the Diptera. 



Dr. Burmeister has made the commonly known human lice and a few others the 

 basis of his first division of the Hemiptera, next preceding the Homoptera, giving them 

 a value parallel to some superfamilies ; and as no proper place can be found for them 

 next to the Heteroptera, we follow his example, but begin the series with this group 

 as a sub-order. 



These insects have a tough, though thin outer integument of moderate flexibility, 

 a flattened body suited for concealment at the roots of hair, fur, and bristles, and 

 strong grasping retractile claws for climbing from one hair to another, or for grappling 

 the cuticle with great tenacity. The transparency of their skin and the slenderness of 

 the sutural impressions render the divisions of the thorax difficult to detect, but upon 

 very close examination, aided by staining fluids, the three principal segments are 

 always found to be present. The pieces of the abdomen are quite distinct, and two 

 or more of the appendages of the anal segment may be easily recognizecL A head of 

 moderate size is let into the front end of the thorax, and is carried horizontally as in 

 the Heteroptera. 



Two prominent characteristics will serve to separate this sub-order from the others. 

 The position of the ten spiracles is upon the upper side of the body, not beneath, and the 

 legs arise from the outer margin of the thorax. These are accompanied by modifica- 

 tions of other values which will be recorded farther on. 



The PEDICULJNA is represented by very small, wingless, elliptical or lyrate insects 

 with a fleshy unjointed rostrum, capable of extension by being rolled inside out, this 

 action serving to bring forward a chaplet of barbs which imbed themselves in the skin 



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