THE TURTLE-BACK SCALE. 



49 



and one deeper indentation behind. The color changes with age from 

 transparent yellow in the young to deepening shades of brown in the 

 adult. ' Individuals attacked by parasites turn black. Until it becomes 

 gravid and swollen with young, the insect is exceedingly thin and trans- 

 parent, the green color of the leaf or bark showing through the body so 

 that the very young Coccid is well nigh invisible. The surface is smooth 

 and shining, with faint, scattered punctures on the disk. The six slender 

 legs are concealed beneath the dilated margins of the body. The male, 

 although for liwny years diligently sought, both in this country and 

 abroad, still remains undiscovered. 



Toinifj Larva. The new-born 

 insect has the usual oval form of 

 young Bark-lice. It is yellowish 

 in color, and has a pair of six- 

 jointed ant enure, and two long 

 bristles at the anal extremity. 



Metamorphoses. The metamor- 

 phoses which take place in this 

 species are very simple, and con- 

 sist in a llul tening and broaden- 

 ing of the form of the larva, and 

 in the gradual loss of external or- 

 gans by disuse. The first to dis- 

 appear are the antennae and the 

 anal bristles; lastly, but not until 

 the body becomes swollen with 

 young, the legs become useless, 

 and are imbedded in the excre- 

 tions, which iinally cement the 

 insect to the surface of the plant. 

 The body of the mother in this 

 last stage of her existence be- 

 comes a caskot filled with the 



young lice. These in due time 



Fio. 11 . Lccantum heupcridvni (Linn.) Adult fe- 

 males, on Oruuge, natural size. (Afi.tr Cowstock.} 



swarm forth together and distri- 

 bute themselves over the plant. 



Restricti >n to youny Growth The young lice invariably settle upon 

 the bark and leaves of tender growth. Even the adult insects do nci 

 appear able to pierce with their beaks the tissues of the plant when 

 hardened by age, and only the gravid and incubating females are found 

 upon parts which have completed a season's growth. 



Gregarious Habits. There is a tendency in the young to kcvp together, 

 and at seasons when the Orange is in active growth, when the p'aut is 

 pushing out an ffbundauce of shoots, the swarming larva do not need 

 to wander far in search of food. The. progeny of each female then set- 

 tle down together, and extensive colonies are formed. These colonies 

 G52I o i 4 



