62 DISEASES OF CROPS. 



and have tidckeiied femora (thighs) which enable them 

 to leap almost like fleas. The species under consideration 

 is black with a yellow stripe on each wing-sheath, and 13 

 very destructive to turnips. " The eggs are laid upon the 

 underside of the rough leaf from June to September, and 

 hatch in seven or eight days' time." The white larvae 

 (whose heads are provided with cutting jaws) live between 

 the cuticles of the leaf, and in about sis or seven days 

 turn to pupae, which bury themselves in the ground. In 

 about fourteen days the perfect insects appear. They 

 live through the winter in a torpid state (under bark, 

 clods of earth, and in manure heaps), reviving in the 

 spring. The spring is the period of special danger, for 

 these beetles most seriously injure the cotyledons or seed- 

 leaves of the young turnip plant. " Many a farmer has 

 seen a promising braird one evening, but not a vestige of 

 green leaf has been visible on the day following. Unfor- 

 tunately, the insect is able to travel miles, even against 

 the wind, to wreck a crop of turnips." There are several 

 other species of the Salticce (besides the one described) 

 which feed upon the leaves of the turnip, and often par- 

 tially or wholly ruin field after field of this crop. The 

 IlalticcB have several.broods in a season. 



Prevention.— (1) Destroy charlock, shepherd's purse, 

 and other cruciferous weeds, for the Halticce feed upon 

 these plants as well as upon . turnips. (2) " Manure 

 liberally, and obtain a firm and thoroughly fine seed-bed. 

 Beware of clods ! Sow the best new seed, and always use 

 the drill instead of broadcasting." (3) Use artificial fer- 

 tilizers in preference to farmyard manure, unless the latter 

 can be deeply buried. (4) Artificial fertilizers should be 

 deposited along the ridges as soon as the latter are made. 

 They not only give vigour to the plants in their early 



