ONE HUNDRED THOUSAND FACTS FOR THE PEOPLE. 4 o S 



■what constricted behind the thorax. 

 From two to five eggs may invariably be 

 found in the abdomen of these, and are 

 easily seen when the insect is held be- 

 tween the light, or mounted in balsam 

 or glycerine. A certain proportion have 

 an entirely different shaped and smaller 

 body, the abdomen being short, con- 



Fig. 48. — Type Radicicola. 



play such an important part in the disease 

 as was at first supposed, may be controlled 

 with sufficient ease by a little care in de- 

 stroying the first galls which appear, and 

 in pruning and destroying the terminal 

 growth of infested vines later in the sea- 

 son. The root-lice are not so easily 

 reached. As the effort will be according 

 to the exigency, we may very nat- 

 urally look to France for a direct 

 remedy, if ever one be discovered. 

 But of all the innumerable plans, 

 patented or non -patented, that 

 have been proposed — of all the 

 many substances that have been 

 experimented with under the stimu- 

 lus of a large national reward, no 

 remedy has yet been discovered 

 which gives entire satisfaction or is 

 applicable to all conditions of soil. 

 Nor is it likely that such a remedy 

 ever will be discovered. A large 

 majority of the remedies proposed, 

 such as the planting of Madia sat- 

 iva among the vines to catch the 

 insect by its viscous property, or 

 inoculating the vines with the es- 

 sence of Eucalyptus globulus, are, 

 upon their face, unworthy of prac- 

 tical consideration, or absurd. 

 These we will pass by, and briefly 

 mention only those which have 

 been more or less productive of 

 good. 



Submersion, where practicable, 

 and where it is total and suffi- 

 ciently prolonged, is a perfect 



a, shows a healthy root; 6, one on which the lice are . Th - • , . th 



working, representing the knots and swellings caused by r< f mea y- , ims ™ ™ &t even ™ e 

 their punctures ; c, a root that has been deserted by them, closest Student might expect, as he 

 and where the rootlets have commenced to decay; d, d, d, finds that excessive moisture is very 

 show how the lice are found on the larger roots ; e, female disastrous to the lice M Louis 

 pupa dorsal view; / same, ventral view; g winged fe-j. f Graveson "(Bouche du 



male, dorsal view ; h, same, ventral view ; t, .magnified at- 1,? \l -r? ^ r ^°_j V ■"" , . 

 tenna of winged insect; /, side view of the wingless female, Rhone)) .France, has ■ abundantly 

 laying eggs on roots; k, shows how the punctures of the proved its efficacy, and has, by 

 lice cause the larger roots to rot. means of it, totally annihilated the 



tracted, and terminating in a fleshy and insect in his vineyard, which was suffering 



dusky penis-like protuberance ; the limbs 

 stouter, and the wings proportionately 

 larger and stouter, with their veins con- 

 necting. This shorter form never has eggs 

 in the abdomen, but, instead, a number of 

 vesicles containing granulations in sacs. 

 These granulations have much the appear- 

 ance of spermatozoa, and seem to have a 

 Brownian movement, but are without 

 tails. 



Remedies. — The leaf-lice, which do not 



from it four years ago. From his experi- 

 ence we may draw the following conclu- 

 sions : 



1. The best season to submerge is in 

 autumn (September and October), when 

 the lice are yet active and the vines have 

 ceased growing. Submergence for 25 to 

 30 days, at this season, will generally rout 

 the lice. 2. A submergence of 40 to 50 

 days, in winter, is required. 3. A vine- 

 yard should never be inundated for a 



