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622 THYSANURA. 



TIIYSANURA. 



Tlie Thysanura are Aviiigless, and undergo no metamor- 

 phosis. There is a great range in the degree of complexity 

 of structnre from Lepisma, the hitter resembling a larviil 

 Perla or Blatta, to Anura. The higher group, or l)ristle-tails, 

 Avhich we may eall Cbaira, comprises the families Lepismatifhp 

 and Campodem. Lubbock has ap[)lie(l the term Collembola to 

 the Podurida^ and Smynthurida^ in allusion to 

 the sucker-like organ situated at the base of tlie 

 abdomen. The Cimira are characterized by 'f/ 

 their well-developed mouth-parts, abdominal 

 feet and bristles or cerci, and the (Collembola 

 by their spi'ing {elater^ its holder {tenaculum^ 

 Fig. 61 7«), as well as tlie sucker or collophore^ 

 as it may be termed ; by the rudimentary mouth- 

 parts and by their diminutive size. '^^Wi^ <o\"a 



These interesting small, Avingless forms also afford a pas- 

 sage from the true winged insects to the Myriopods, Scolo- 

 pendrella being a connecting link, having the head and antenna" 

 of Campodea, and the abdominal legs of the Myriopods. Even 

 the i)lace of abdominal legs in Lepisma is supplied by the 

 rows of small stylets which prop up the long slender 

 abdomen. 



Lepismatid.?^. Burmeister. Bristle-tails. These agile crea- 

 tures, which are revealed by turning over stones and sticks in 

 damp situations, and are often seen about houses, have a long 

 flattened body, Avith metallic scales, in form somewhat like 

 those of butterflies. The antennre are very long, setiform, 

 many-Jointed ; the mouth-parts are free, with long palpi ; the 

 maxillary palpi being seven-jointed and the labial palpi four- 

 jointed. The mandibles are stout, sunken in the head, and 

 armed with teeth for gnawing. The prothorax is very large, 

 and all the rings of the body are of much the same size, so 

 that the insect bears a general resemblance to the Myriapods. 

 The anal stylets are long and large, which with the smallei 



