NOTES ON Two MILLIPEDES. 3 



Mr. F. V. Theobald ' 3 more recently records damage to potato 

 crops, by J. pulchellus, and another species, and a species of 

 Polydesinns. 



During 1903 I received potatoes very badly infested from 

 Stafford. In this case both species of millipede were present, 

 Polydesinus being, perhaps, the more numerous. 



In September a correspondent sent me some seedlings of the 

 wallflower (Cheiranthus cheiri), the roots of which were covered 

 with young and medium sized specimens of J. pulchellus and very 

 small examples of P. complanatns. Of the former there were 

 6080 on each plant, and 12 20 of the latter. The whole of the 

 secondary roots had been bitten away, and the epidermis almost 

 entirely denuded from the tap-root. Further there were small 

 irregular shaped holes eaten out of the root. 



In discussing the matter with him he mentioned that he had 

 found beans (Viciafaba) eaten, and in the holes numerous specimens 

 of Jnlus, but was doubtful as to whether or not they were the real 

 culprits. Various writers have stated that the millipedes are not 

 the culprits, and this opinion, I find, is largely held by horticulturists 

 and others. This being so, it seemed desirable to place the matter 

 beyond all doubt, the following experiments were therefore under- 

 taken. 



A plentiful supply of both species was obtained from the wall- 

 flower roots, and these were placed in soil, which had been very 

 carefully, but unsuccessfully examined for traces of any other 

 animal life. The soil was then placed in nine glass vessels, 

 with about 50 specimens of each millipede in each. Into these the 

 seeds of Phaseolus uiultifloris were sown on October 6th and the 

 vessels were covered with glass lids. On the second day all the 

 beans were found to have a few of the millipedes upon them, and 

 these became more numerous later. On October 22nd, very small 

 holes were observed, which rapidily increased in size until the 28th, 

 when all the beans were removed and washed in 90% alcohol. 

 The soil, etc., thus removed from the seeds was then dried and 

 very carefully examined, but excepting the two species of millipedes 

 no other animals were found. The soil from the glass vessels was 

 then dried, and carefully worked through, with a like result. 



The broad beans Viciafaba were sown in six similar vessels 

 with the following results. On the sesond day they were noticed 

 to have numerous specimens of Polydesuins running about them, 

 but it was not until the sixth day that Jiilus was noticed. On 

 October 26th three or four specimens were taken up and all were 

 found to be infested with both Julus and Polvdesiiius, while the 

 cotyledons were riddled with holes, more so than those of Phaseolus. 



3. First Rpt. on Economic Zool., 1903, Brit. Mus. (Nat. Hist.), pp 84 & 86. 



