138 JOURNAL, OF ENTOMOLOGY AND ZOOLOGY 



is pulled into the mouth by the retraction of the mandibles 

 assisted by the upper and lower lips, the coarse food being 

 crushed by the ventral teeth of the mandibles. 



Except in the canyons, the best collecting time in Southern 

 California is in the winter, due to the absence of rain in the 

 summer. The CoUemboIa do not exist here in as great 

 abundance as reported from other places, because of the dry 

 climate. The only ones I have found in any great number 

 were a species of Achorutes found in a flume in an orange 

 orchard after a hard rain. They were several inches deep in 

 this flume and would have filled several gallon pails. Also all 

 the rotten oranges in the orchards were blue with this species. 

 They were also found in great numbers on pools in a newly 

 ploughed field after a hard rain. 



ECONOMIC IMPORTANCE 



Until recently, the CoUembola were not considered of much 

 economic importance and very little attention was given to 

 them, due no doubt to their minute size and their seeming 

 insignificance. Most authorities considered that they were 

 followers of decay rather than the primary causes of it, that 

 their jaws were too weak to enable them to masticate a root 

 or leaf and that they didn't attack a plant until some other 

 insect had first inflicted an injury. During the last few years, 

 however, this problem has been investigated and it has been 

 found that the CoUembola do cause injury to plants, and often 

 serious injury. References in the literature are very few, but 

 among the earlier ones we find that Mr. Curtis in his work 

 on farm insects says, "In Nova Scotia the crops of turnips 

 and cabbages are principally destroyed whilst in the seed-leaf 

 by some Smynthurus, the size of a pin's head and nearly 

 globular. It hops with great facility and may be foiand on 

 every square inch of old cultivated land, 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, with which they are almost always 



