PETTIT ON SCALE INSECTS OR COCCID.^. 79 



au<l soiup arc covcicd wiili a \\a\v or pajjery shield. The lac insect 

 secretes slicllac and lives in cavities in tlie mass. The female of Coccus 

 cacti, the cochineal ijisecl, is free for her entire life and wanders at 

 will over the cactus until she commences to lav her ej;j;s. 



There are manv insects of economic im])ortance in this family: 

 china-wax is ma(h' from one si»ecies, shellac and cochineal fr(»m two 

 others. The cottony cusiiion scale nearly destroyed the orange j)lanta- 

 tions in California before another insect, yoiius cardiiialis, could be 

 inn)orted to destrov the scale. In our ow-n state there are two verv 

 serious scales, the San Jose scale and the European Fi-uit scale, which 

 have been the object of legislation. 



The division of the family into sub-families ^and these into genera 

 is here «;iven for Michijian only. The foUowinjj;- list gives the genera 

 now found or likely to be found in Michigan. f 



44 

 The asterisks ( * ) imlicate genera already found in the state. 



In the l)ias])in;e the life-history is substantially as follows: The eggs 

 are hatched usually outside the body of the mother but in some species 

 they are hatched inside, the young issuing alive. The young louse, 

 just from the egg, has antenna^ and six legs like an ordinary insect. 

 The tw^o sexes are usually indistinguishable at this stage. The little 

 fellow, so small as to be invisible except when moving, runs about for 

 a few houi-s and then settles down, inserts its long thread-like beak 

 in the host i)]ant and commences to suck. From this tinu^ the ])Osition 

 of the insect is fixed. It never moves from the spot first chosen, but in a 

 short time, a few hours ordinarily, commences to secrete the shield or 



t This list includes several species commonly imported on fruit. 



