140 JOUKNAX, OF ENTOMOLOGY AND ZOOLOGY 



off wlien handled. It was found on examination that in tlie 

 damaged buds there were several Collemhola of the species 

 Seira nigromactdata Lubb. He found that the insect was 

 attracted by the resinous gum and as soon as the bud opened 

 it made its way to the base of the young leaves and commenced 

 to bite them. 



I had some specimens of Aphorura inermis sent to me which 

 were found inflicting damage to tender roots of young plants 

 near Santa Barbara. This is the onlj^ instance of injury that 

 has come to my notice here in California. In all the orange 

 groves in and around Claremont this year (1914) the rotten 

 oranges were covered with Collemhola of the genus Achorutes 

 but in no case were they found attacking the good fruit. 



DISTRIBUTION 



Insects are among the most widely distributed of the animal 

 groups and the Collemhola are among the most widely dis- 

 tributed of these. This is due to the fact that they are not 

 specialized in regard to their food, feeding on small particles 

 of organic matter ; that moisture is important to their exist- 

 ence ; that they are tolerant of extremes in temperature ; and 

 that these simple conditions can be found almost anywhere. 



The region in which I have been working is about forty miles 

 wide and sixty miles long, extending from the Sierra Madre 

 Mountains on the north to the ocean on the south. This region 

 is varied and a most favorable one, containing, as it does, 

 mountains, canyons, hills, valleys, swamps, and ranging in 

 altitude from sea level to 10,000 feet. I, therefore, had a wide 

 range of conditions from which to studj' the Collemhola and 

 as is to be expected, found many differences (figures 1 and 2). 



Folsom (1901) has written an article on the distribution of 

 Ilolarctic Collemhola, the only contribution on this subject. In 

 it he states that no less than one hundred and fifty-two species 

 of Collemhola are known to occur in North America, of which 

 thirty at least are shared with Europe. Since then this number 

 has been increased. Of those seven that Folsom lists as occur- 

 ring abundantl}' throughout Europe and the United States, I 



