SUBFAMILY MARGARODINAE 89 



legs are fitted for digging. The body is never provided with an anal 

 cleft and opercula, an anal ring and anal ring setae, anal lobes and anal 

 setae, octacerores, pilacerores, or ceratubae. The caudal end of the rec- 

 tum is not chitinized, forming a rectal tube provided with one or more 

 rings of anacerores excreting a long glassy tube of wax. The caudal 

 abdominal segment is not short, narrow, and projecting. 



The male has compound eyes and may have an ocellus along the 

 caudal margin of each compound eye. The abdomen is not provided with 

 lateral filaments. The caudal end of the dorsal aspect of the abdomen 

 bears two tufts of long glassy filaments of wax. The stylus is apparently 

 wanting. 



This subfamily is best known from its typical genus, 

 Margarodes. This was erected in 1828 by Guilding to include some 

 insects found by him in the soil and in the nests of ants on the 

 island of Bahama. The species, because of its association with 

 ants, was given the name of formicarum. The cysts of the insects, 

 known as ground pearls, occur in the soil in prodigous quantities 

 and show in great number when the soil is plowed. Riley states 

 that in certain parts of Florida they compose over one-half of the 

 soil. In the Bahamas they were known according to Guilding as 

 ant-eggs and were strung into necklaces and manufactured into 

 various fancy articles and used for ornamental purposes long 

 before they were recognized as one of the stages of an insect. A 

 similar use for ground pearls has been reported by other writers, 

 who have seen ornaments made by the use of ground pearls as 

 beads from South Africa and Australia, two South African species 

 have been described since but the Australian species is still 

 unknown. Guilding mistook the filaments of wax excreted from 

 the openings in the cyst over the thoracic and abdominal spiracles 

 for special organs developed for obtaining moisture by capillary 

 attraction and named them siphones. 



A complete detailed account of the serial development of any 

 species of Margarodes from the egg to the adult has not been 

 made. The number and form of the various nymphal stages of 

 the female has not been determined and practically nothing is 

 known as to the development of the male. The following account 

 is based upon that of Green which is the most complete published 

 thus far. 



The eggs are deposited in the ground in a mass of filaments 

 of wax excreted by the adult female. The nymphs of the first 

 stage are typical in form and usually provided with three pairs of 

 legs. This stage in one species, mediterraneus, has only the pro- 

 thoracic legs present. The antennae in the first nymphal stage 



