iy4 The Irish NatiDalist. September 



ON TWO COU^EMBOLA NEW TO THE BRITANNIC 



FAUNA 



BY PROF. GEO. H. CARPENTKR, B.SC , M.R.I. A. 

 [Read before the Dublin Naturalists' Field Club, I4tli April, 1908.] 



Both the species of Springtails or Collcmbola described in 

 this paper belong to the Isotomince, a group regarded by 

 students as among the most primitive of the order, and cha- 

 racterised b3^the absence of scales, the close equalitjMn length 

 of the third and fourth abdominal segments, and the presence 

 of a well-developed spring inserted, in some cases, evidently 

 on the fourth, in others apparently on the fifth abdominal seg- 

 ment. Moreover, both are geographically members of the 

 Northern faunistic group, and one is so characteristically 

 arctic and alpine in its range that its presence in our islands 

 is distinctl}^ noteworth}-. In the mode of their occurrence, 

 however, there is a marked difference between the two species. 

 One has been found onl}^ beneath stones in our hill-streams 

 at a considerable elevation. The other has drawn attention 

 to itself by its presence in vast numbers on tobacco plants in 

 a single lowland localit3\ 



IsoToMA TENELLA, Renter, 

 This species was noticed in large ntimbers during April, 

 1907, on tobacco seedlings growing near Kilkenn}^ by Mr. G. 

 W. Keller, the tobacco expert of the Irish Department of 

 Agriculture. The leaves of the young plants were covered 

 with little dark-grey insects, which microscopic examination 

 showed to be referable to hotoma icnclla^ As the epidermis 

 of the leaves was abraded, and the intestines of the springtails 

 contained chloroplasts, there can be no doubt that they had 

 fed on the leaf-tissues. The species, therefore, must be added 

 to those Collembola which are known to be directly injurious 

 to the higher plants, although, as a rule, the members of this 

 order feed on decaying organic matter The introduction of 

 an exotic crop-plant, such as tobacco, into the countr}' affords 

 to the biologist a good opportunit}- of noting the effect of 

 change of environment on the native fauna. In the present 

 instance the vicinity of this new and seemingl}' appropriate 



