Hubert M. Morris 301 



The nitrogen content of the following groups was obtained: Ela- 

 teridae larvae, Collembola, Formicidae, Oligochaeta {Terricolae), Myriapoda 

 and Oligochaeta (Limicolae), the percentage of nitrogen in the dry weight 

 being: Elateridae larvae 10*65 per cent.; Collembola 11-18 per cent.; 

 Formicidae 10-92 per cent.; Oligochaeta {Terricolae) 9-4 per cent.; Myria- 

 poda 4-88 per cent. ; Oligochaeta (Limicolae) 6-26 per cent. 



The total weight of nitrogen per acre contained in the bodies of the 

 above groups in the manured plot is approximately: Elateridae larvae 

 206-0 gm.; Collembola 8-5 gm.; Formicidae 306-6 gm.; Oligochaeta (Ter- 

 ricolae) 4:626-0 gm.; Oligochaeta (Limicolae) 97-Ogm.; Myriapodal86i'9 gm. 



Assuming that the remaining insects are of the same average nitrogen 

 content, the total nitrogen of all the insects in an acre of the manured 

 plot is 687-7 gm. 



The nitrogen contained in the Oligochaeta (Terricolae and Limicolae) 

 and Myriapoda is 6587-9 gm. per acre of the manured plot. These groups 

 include 6,400,668 of the 7,373,730 invertebrates other than insects, the 

 remaining 973,062 consisting chiefly of Arachnida, with some Isopoda 

 and a few Gastropoda. Assuming their nitrogen content to be the same 

 as that of the same number of insects, it would be 74-0 gm. giving a 

 total of 6661-9 gm. 



The total nitrogen of the fauna of an acre of the manured plot is thus 

 7349-6 gm. or 16-2 lbs. 



In the control plot the nitrogen contained in the bodies of the same 

 groups is: Elateridae larvae 169-0 gm.; Collembola 2-4 gm.; For^nicidae 

 71-5 gm.; Oligochaeta (Terricolae) 2128-0 gm.; Oligochaeta (Limicolae) 

 21-4 gm.; Myriapoda 920-1 gm. 



Again assuming that the remaining insects are of the same average 

 nitrogen content, the total nitrogen of all the insects in an acre of the 

 control plot is 313-3 gm. 



The nitrogen contained in the Oligochaeta (Terricolae and Limicolae) 

 and Myriapoda is 3069-5 gm. per acre of the control plot. 



These groups include 2,131,311 of the 2,478,112 invertebrates other 

 than insects in an acre of the manured plot. Assuming that the remain- 

 ing 346,801 invertebrates have the same nitrogen content as the same 

 number of insects, their nitrogen content is 26-4 gm. 



The total nitrogen contained in the bodies of the fauna of an acre of 

 the control plot is thus 3409-2 gm. or 7-5 lbs. 



These amounts of nitrogen are equivalent to the nitrogen contained 

 in 103-6 lbs. and 48-0 lbs. of nitrate of soda in the manured and control 

 plots respectively. 



