THE CUCUMBEK AND TOMATO EELWORM. 55 



paratively small, but it has not yet been determined when fertilisa- 

 tion takes place. However, it must occur long before the female 

 cysts are fully grown. On an average each female cyst produces 

 something like two hundred eggs. It takes about one month for 

 the eggs to develop into full-grown males or pregnant females. 

 The following will, therefore, give us some idea to what extent 

 this pest can multiply, for let us suppose that one female cyst pro- 

 duces 200 eggs, allowing one half of these to be males, in one 

 month there would be 10,000 female worms, in two months 

 1,000,000, in three months 100,000,000, and so on. These 

 figures must not be taken as what does occur, but are only for the 

 purpose of illustration. A great deal more might be written on 

 the life-history of this pest, but I think the above is sufficient to 

 give those who are troubled with it some idea of what they have 

 to deal with. 



For remedies I would refer the reader to a discussion now 

 going on in the Journal of Horticulture, but from the brief des- 

 cription I have given it is easy to see that we can only hope to 

 eradicate the pest by taking radical measures as soon as it makes 

 its appearance. When once established, it is, as far as my expe- 

 rience goes, impossible to get rid of it. In conclusion, I have to 

 thank Mr. F. S. Hutchason, Wormley, Herts, for the use of the 

 diagrams, which, I may say, were taken from living specimens we 

 examined under the microscope. 



[Miss Ormerod has done splendid work in many other ways 

 than in giving the first account in this country of the life-history 

 of Heterodcra radicicola, from information largely supplied by Dr. 

 J. Ritzema Bos, Prof Atkinson, and Dr. J. C. Neal ; but so far as 

 we know the world is indebted to the late Rev. M. J. Berkeley for 

 its discovery. Cucumber root galls, also a cyst female with eggs 

 and young larvae, were figured by him in the Gardeners^ Chronicle 

 in April, 1855. Mr. W. G. Smith gave an excellent illustration of 

 eelworms in Cucumber roots in ihc Journal 0/ Horticulture, Jan. 

 14th, 1875, taken from the most gigantic example of Cucumber 

 root clubbing we have ever seen. Mr. Smith was well acquainted 

 with Mr. Berkeley's female Heterodera. which was at first taken 

 for a large vegetable cell in which the eggs were encysted. Pro- 

 fessor Percival has closely investigated the subject, and is as 



