94 JOURNAL OF THE 



is the slipping of the head from the wall of the head end of the 

 cvst. At the saQie tiaie the thick body of the male begins to 

 elongate and double up inside the cyst, while the tail end, stout 

 and blunt, begins to curve around. This makes the third moult. 

 (See Fig, 21, Plate IV). While the male is elongating and coil- 

 ing up in the cyst it begins to moult again, making four moults. 

 The very thin skin can be seen partly slipped off the worm 

 while yet within the cyst (Fig. 21). The male continues to elon- 

 gate and l)ecome more slender until it is coiled three, four, or 

 more times, dependeut on the length of the cyst, within the walls 

 of the cyst, which still retain perfectly the shape of the cyst 

 when the transformation began. Even the exsertile spear moults, 

 for its '^ mould" is left in the head end of the cyst, while the 

 skin of the larval tail still projects as a slender process. The 

 niale coiled within this perfect wall of the cyst is a very beauti- 

 ful object. Figs. 21 x and 22 represent these. During this 

 transformation the sexual orgaus of the male have become 

 matured. It no^v breaks through the wall of the cyst and the 

 surroujiding tissue and travels blindly through the maze of cells 

 until it comes to its mate, when it pairs aud then dies. Fig. 23 

 represents a male coming from its cyst. Fig. '2'iz a male of 

 Heterodera radicicola removed from a cyst. 



Structure of the Male. — It may be well now to note some 

 thinirs about the structure of the male which were not described 

 in the section upon the '' General Characters of the Female 

 Cyst." It is from 1 mm. to 1.5 mm. (one twenty-fifth to one 

 seventeenth of an inch) long and about .043 mm. (seventeen one- 

 thousandths of an inch) broad near the middle. Its body a 

 little less in diameter at the posterior end; the anterior half of 

 the body gradually tapers to the head end, which is about half 

 the diameter of the middle. The body wall is beautifully marked 

 by prominent transverse strife broader and much more distinct 

 than in the larval stage. The head, exsertile spear and oesopha- 

 gus have been described. The excretory canal on the ventral 

 side opens a little posteriorly to the muscular bulb. The caudal 

 end (tail end) is slightly curved, and very near the end are the 

 two curved spicules. 



