34 ROOT-KNOT AND ITS CONTROL. 



MALE. 



The development of the male after the larval stage differs greatly 

 from that of the female. Within the old larval cuticle a new cuticle 

 is formed. The nematode pulls itself away from the old skin, remain- 

 ing mclosed by it, however. The tail is rounded here, too, but the 

 anus is ventral instead of terminal. The whole body now elongates 

 very rapidly, becommg correspondingly slender (PI. I, figs. 13 and 14). 

 This necessitates a coiling in order still to remain within the old skin, 

 imtil it is coiled two or three tunes. When tliis development is com- 

 plete (PI. I, fig. 15) it breaks its way out of the old cuticle, which has 

 retained its larval shape, and passes through the tissues and probably 

 even outside of the root in search of a female. Just prior to leaving 

 the old larval skin after undergoing tliis metamorphosis the nematode 

 does not molt again, as some assert. 



The mature male differs greatly in many particulars from its appear- 

 ance just previous to the last molt. The form is about like that of 

 the larva on emerging from the egg, i. e., long and slender, differing, 

 however, in the greater size and in the short, rounded tail. The 

 length is usually 1,200 to 1,500 //, the thickness 30 to 36 pt. The tail 

 is short and rounded, not tapering, the distance from the anal open- 

 ing to the posterior end of the body bemg not more than 13 to 18 /t. 

 The cuticle over the whole body is very distinctly marked with trans- 

 verse rings extending entirely around the body and 2 to 2.5 /i apart 

 (shown m section in PL I, fig. 16). Except in profile it is only the 

 furrows between the projecting segments of cuticle that are visible. 

 These cuticular rings, which are also visible on the anterior portion 

 of the mature female, are not visible, at least at ordinary magnifica- 

 tion, in the larvae. 



The alimentary canal is essentially as in the^ young larva. The 

 spear, however, deserves special notice. It is larger than in the larval 

 stage or than in the mature female, being usually about 24 /i in 

 length (rarely as short as 18 /< or as long as 28 p). The knobs at its 

 base are promment. Above the knobs the sides are parallel for about 

 half way and then taper to the fmely pointed tip. The canal through 

 the spear is rather distinct. The body wall is about 1.5 /i thick. 

 However, at the truncate anterior end it is between 5 and 6 // thick. 

 The anterior 2.5 // of this is a sort of hood, or cap, set off from the 

 rest of the body by a sharp furrow. L>dng in the termmal body 

 wall, well below this hood and projectmg but slightly into it, is a 

 series of six radiating perforated lamellae (apparently chitmous in 

 nature), narrow at their anterior ends and broad basally. Viewed 

 from the side they are approximately right triangles, the hypotenuse 

 being somewhat wavy. The bases of the lamella? radiate from a 



217 



