NO. 9 cuckler: nematode parasites 141 



proximal end of the spicule is slightly expanded at the point of attach- 

 ment of the spicular muscles. The spicule width at this point is about 

 0.042 mm. ; from this region the spicule gradually tapers to end in a 

 fine sharp point. The accessory piece is well developed, V-shaped, and 

 has a maximum width of 0.046 mm, and a length of about 0.076 mm. 

 Posteriorly it tapers to a bluntly rounded, ventrally directed, hooked tip. 



There are four pairs of genital papillae located at the ventral body 

 cleft (fig. 6). Three pairs are circumcloacal and one pair is caudal in 

 position. Two of the pairs of circumcloacal papillae are precloacal in 

 position. The most anterior and ventral pair of this group is well de- 

 veloped and situated on projections from the body. These papillae, as 

 well as the second pair of precloacal papillae, are considered to be sessile. 

 The second pair of precloacal papillae can not be seen in the ventral 

 view of the caudal region because they are small and dorsal to the large 

 precloacal pair. The third pair of circumcloacal papillae is pedunculated 

 and is adcloacal in position. These papillae are situated on stalks which 

 extend nearly to the posterior extremity of the accessory piece. The 

 fourth or caudal pair of papillae arises from the caudal stalk at about 

 the junction of its fourth and last fifths. These papillae are well de- 

 veloped and pedunculated. Summarizing, there are two pairs of pre- 

 cloacal sessile papillae, one pair of adcloacal pedunculated papillae, and 

 one pair of pedunculated caudal papillae. 



The caudal alae are wide and deep, and extend from the base of 

 the tail to the base of the caudal papillae. The deepest point of the ala 

 is at about its mid-region, where it extends ventrally to the level of the 

 ventral precloacal papillae. The alae extend laterally to about the body 

 width at the anterior end of the tail, but taper slightly at their posterior 

 limits. 



Female: The vulva is situated posterior to the middle of the body; 

 it ranges from 2.6 to 3.4 (average 2.9) mm. from the anterior end. 

 In the mature animals the vulva is surrounded anteriorly by a promi- 

 nent cuticular expansion. The vagina is a well-developed muscular or- 

 gan, which meets the body wall at an oblique angle. A common uterine 

 stem connects the divergent uteri to the ovejector and vagina. The va- 

 gina varies in length from 0.49 to 0.56 mm., and its width is about 0.08 

 mm. Between the vagina and the common stem of the uteri there is a 

 less muscular structure, the ovejector. This structure is about 0.20 mm. 

 in length by 0.07 mm. in width. At both ends it is equipped with valvu- 

 lar, bulblike structures. 



