BLACK FLY. 95 



Of t 

 two preceding families. 



longest known species of this group, which is closely allied to the 



THRIPID^E. 



Wings long, narrow, equal, veinless, with long fringes, laid 

 horizontally along the back when at rest; tarsi two-jointed; 

 metamorphosis complete ; pupa active. 



This is a family of uncertain position ; it was originally placed 

 by Linne" at the end of the ffemiptera after Coccus, and is still 

 regarded by some entomologists (e.g. Pascoe) as Hemipterous. 

 Other authors have referred it to the Orthoptera or Neuroptem, 

 while others again have regarded it as entitled to form a distinct 

 Order, under the name of Thysanoptera. It includes very small 

 insects, which are generally met with on plants, to which they some- 

 times cause much injury by absorbing their juices. Some species 

 met with in gardens and greenhouses are known to gardeners as 

 the " Black Fly ; " but the most frequently observed of any is the 

 small black insect met with in wheat, infesting both the stalk and 

 the ear, and often to be found nestling in the furrow of the seed 

 itself. The female is apterous, and the larva and pupa are yellow, 

 the latter with short wing-cases. Its name is Thrips Cerealium, Hal. 



MALLOPHAGA. 



Wingless, mandibulate insects, not undergoing a metamorphosis, 

 and parasitic upon birds. 



This group, which includes the Bird-Lice, was formerly regarded 

 either as a separate Order by itself, or was united with the 

 Pediculidcs to form the Order Anoplura. By modern writers it is 

 generally treated as a degraded family of either the Hemiptera or 

 the Neuroptera. Westwood, however, excludes the Mallophaga, 

 Anoplura, and Thysanura from the insects altogether, regarding them 

 as a distinct class, under the name of Ametdbola, chiefly on account 

 of the total absence of either wings or metamorphoses in these 

 groups. 



The Mallophaga differ considerably in structure, but are gener- 

 ally longer and more slender than the Pediculidce, to which they 

 have a great analogical resemblance, though differing so much in 

 structure that they are usually placed in distinct Orders. They 

 are all parasitic on birds, feeding on the soft parts near the roots 

 of the feathers. 



