DEVELOPING PARASITIC FEMALE 



349 



glandular secretions sug- 

 gests two functions ; e .g. , (1 ) 

 solvent action on the chitin 

 of the host at the time the 

 nema drills into the host, 

 and (2) an aseptic effect to 

 aid in healing the wound 

 thus inflicted on the host. 

 Small, irregularly poly- 

 hedral birefringents occur 

 among the spherical gran- 

 ules of the intestine. Very 

 small amphids are believed 

 to occur. There are no 

 eyespots. Sometimes the 

 terminus of the female is 

 marked by the presence of 

 one or two small, back- 

 ward-pointing, short, trun- 

 cate, cylindroid mucronea, 

 about one micron long and 

 about equally wide. The 

 blind end of the gonad, half 

 as wide as the body, lies 

 near the middle of the 

 nema and is directed for- 

 ward. Passing backward 

 two body widths, the gonad 

 becomes one-third as wide 

 as the body; five body 

 widths back it is only 

 about one-fifth as wide as nrt rnt 

 the body. It then expands 

 a little, and is separated 

 from the large sperm recep- 

 tacle comprising the rest of 

 the gonad, by a rather dis- 

 tinct constriction. Begin- 

 ning narrow near the head, 

 the lateral chords widen 

 regularly until they reach 

 their full width, about 

 one-third that of the body, 

 a little behind the nerve- 

 ring. Here, at intervals 

 equalling the body diam- 

 eter, the lateral chords 

 carry broad ellipsoid cells 

 about one-fourth as wide 

 as the body, containing 



'Iff 



Fig. 5. Quarter grown 

 Howardula benigna removed 

 from the body cavity of the 

 cucumber beetle, Diabrotica 

 vittata. The striations of 

 the cuticle are much too 

 fine to be shown in a figure 

 of this magnification; the 

 features shown at ruga are 

 folds in the cuticle depend- 

 ent on the attitude of the 

 nema. The narrow, imma- 

 ture sexual organ is shown 

 dark. The spermatheca, 

 spthc, with its excessively 

 minute sperm elements, is 

 shown overlaid by the much 

 coarser tissues of the body 

 wall. A few sperms occur 

 near the vulva. The uterus 

 ultimately enlarges so as 

 nearly to fill the body cav- 

 ity; the ovary, ovr, mean- 

 time, is shoved forward into 

 the front end of the body, 

 trm ovr, present position of 

 blind end of ovary. 



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