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NEUROPTERA. 



Synopsis of the British Psocid^e. 

 By Dr. Hagen. 



The Psocidce are remarkable for tlieir minuteness and 

 agility ; they are among the smallest insects known. The 

 chief characters are : head large, almost triangular, placed 

 nearly perpendicularly ; reticulate eyes, round, large; ocelli 

 wanting in some, small, thiee in number, close together in 

 the centre of the crown ; antennae slender, long, sometimes 

 much longer than the animal ; the two basal joints generally 

 more robust ; the remainder form a multi-articulate (11 to 

 25) bristle ; labrum large, convex, with conspicuous para- 

 chila within ; mandibles corneous, strong, with the apex 

 curved ; maxillae membranous, the inner lobe, however, cor- 

 neous, with a straight sharp edge notched at the tip; outer 

 lobe thicker and larger; palpi quadri-articulate, the last joint 

 knob-like, projecting beyond the mouth ; labium small, on 

 each side with a rudimentary labial palpus ; on the labium 

 reposes the much swollen laterally corneous tongue (hypo- 

 pharynx) ; prothorax very short and small ; meso- and 

 meta-thorax larger, quadrate ; legs short, the posterior some- 

 times with thickened thighs, leaping legs ; tarsi two or 

 three-jointed ; abdomen ovate ; the generative organs of the 

 male presenting a very complex apparatus of hooks, of the 

 female a sort of oviduct ; wings seldom entirely wanting, the 

 1861. c 



