COLEOPTERA OR BEETLES. 



149 



Shepherd's purse and Jack-by-the-hedge ; but as soon as the 

 turnips show above-ground, away they fly and nip off the two 

 cotyledons just below their junction, thus completely destroying 

 the young plant. Should the weather be warm and dry, the 

 damage they do is tremendous, often necessitating two or more 

 sowings of seed before a plant can be obtained. They are very 

 susceptible to damp and cold, and then become sluggish, — a 

 feature usually noticed early in the morning after a heavy 

 dew. When the turnips get into rough leaf the damage they 



Flu. 69. — 1, The Tuhnip Flea Beetle, much magnilied ; 2, nat. length and wing 

 expanse ; 3, nat. size ; 4, 5, egg, nat. size and mag. ; 6, 7, mine, and cuticle eaten away 

 by larva ; 8, 9, larva, nat. size and mag. ; 10, 11, pupa, nat. size and mag. 



do is not so great ; but even then they are destructive, eating 

 away at the tissues until the leaves are almost skeletons. 

 The female lays her eggs upon the turnip leaf, on the rough 

 under-surface, often choosing a place near the ribs to deposit 

 them. In from four to six days the ova hatch into minute 

 larvae with large brown heads and biting jaws, six small jointed 

 legs in front, and a number of hairs over the body. The 

 larvae at once burrow into the middle of the turnip leaf, and 

 there tunnel about in the parenchyma for six or seven days, 

 when they attain their fully fed state, being about one-sixth of 

 an inch long. On reaching maturity they leave the leaf and 



