CHAPTER VIII 



SUBFAMILY MARGARODINAE 



The Ground Pearls 



The body of the adult female is rotund or strongly convex on the 

 dorsal and flat on the ventral aspect. The cephalic, caudal, and lateral 

 margins are broadly convex. The segementation is indicated. The cau- 

 dal end of the body is not inflated and the cephalic and lateral margins 

 are not provided with a keel. The antennae are small, consist of six to 

 nine segments, and are articulated to the ventral aspect of the head near 

 each lateral margin. The eyes are wanting. The mouth-parts, rostrum 

 and rostralis, are wanting. The legs are present and always different 

 in form. The prothoracic legs are fitted for digging. The profemora 

 are greatly enlarged and swollen, their tibiae are short, their tarsi and 

 claws are fused and together are much longer than their tibiae. The 

 mesothoracic and metathoracic legs are normal in form, their femora 

 are not swollen and their tarsi and claws are not fused. The claws are 

 as long as or longer than their tibiae. The trochanto-femoral and the 

 tibio-tarsal sutures are always distinct. The spiracles of the mesothorax 

 and metathorax are normal in form and ventral in position. The meso- 

 thoracic spiracles are never located near the anus. The spiracles of 

 the first abdominal segment are ventral in position and those of segments 

 two to seven or eight are usually dorsal. The spiracular tracheae of the 

 abdominal spiracles are never provided with one or more rings of 

 cerores. The stigmatic clefts, spinae, and canellae are wanting. The 

 abdomen is about as long as the head and thorax together. It is convex 

 on the dorsal and ventral aspects, never depressed. The lateral mar- 

 gins are uniformly convex. All of the segments are fully exposed and 

 subsimilar in appearance, none are retracted to form a marsupium. 

 The abdomen is never provided with an anal cleft and opercula, an 

 anal ring and anal ring setae, or anal lobes and anal setae. The caudal 

 abdominal segment is never short and narrow and extending beyond 

 the other segments. The body is provided with cerores, none of which 

 are octacerores or pilacerores, and never provided with ceratubae. The 

 body is never enclosed in a resinous cell with three adjacent openings 

 or covered by a scale with or without exuviae, but may be more or less 

 covered with a white mealy or powdery wax or loose woolly threads of 

 wax. The rectum is never provided with a long glassy tube of wax with 

 a chitinized rectal tube bearing rings of anacerores. The body is never 

 naked and gall-like in form. 



The female nymphs, except the last nymphal stage, are provided 

 with a one-segmented rostrum. The three pairs of legs or at least the 

 prothoracic pair are present in the first nymphal stage and dissimilar in 

 form. All of the legs are wanting in one or probably more nymphal 

 stages. The profemora, when present, are enlarged and the prothoracic 



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