ECONOMIC IMPORTANCE OF THE 

 COLLEMBOLA 



From an economic point of view, the Collembola are re- 

 garded as of mmor importance when compared with certain 

 other better known insects ; yet some of them have been accused 

 of rather serious depredations upon garden crops. Harris, in 

 speaking of some of the Sminthuri, says: "Several years ago I 

 observed that cucumber vines were much infested by some 

 minute jumping insects. They injured the vines very much 

 by eating holes into, or puncturing the leaves, and were ex- 

 pelled by dusting the plants with flour of sulphur." 



Mr. Curtis, in his work on farm insects, says : 'Tn Nova 

 Scotia the crops of turnips and cabbages are principally de- 

 stroyed, whilst in the seed-leaf by some Smynthurus, the size 

 of a pin's head, and nearly globular. It hops with great facility 

 by means of its forked tail and may be found on every square 

 inch of all old cultivated ground, but it is not plentiful on new- 

 land." 



Dr. Asa Fitch says : "Our gardeners universally regard 

 these fleas as being injurious, but not so severely injurious as 

 the larger-sized flea-beetles (Haltica) with which they are almost 

 always associated. And this appears to be a correct estimate 

 of their character. I have sought to ascertain the exact nature 

 of the injury which they do, and from the best observations 

 which I have yet been able to make, I think these fleas never 

 perforate holes in the leaves or gnaw their texture where it is 

 gre,en and in a healthy growing state. Their small jaws are 

 probably too soft and weak to enable them to break down and 

 masticate the substance of the leaf. But when a flea-beetle per- 

 forates a hole in the leaf, these garden fleas afterwards gather 

 around the perforation to feed upon the soft matter which is 

 there formed by the evaporation of the exuding juice. This 



