NO. 9 cuckler: nematode parasites 149 



anterior of the distal quarter the spicule is dorsoventrally thickened. 

 There is a well-developed, V-shaped accessory piece, measuring 0.052 

 mm. in width by 0.075 mm. in length. The tip of the accessory piece is 

 directed posteriorly and laterally, usually to the right. In no instance 

 was the tip ventrally directed or hooked. 



Female: The reproductive system is typical. The vulva is slightly 

 anterior to the middle of the body. The average distance from the an- 

 terior of the body to the vulva is 2.96 mm., which is about 0.01 mm. 

 less than half the body length. The anterior margin of the vulva is sur- 

 rounded by a cuticular expansion. The vagina is large and muscular, 

 being 0.80 mm. in length by 0.09 mm. in width. The internal end of 

 the vagina is swollen into a bulb-shaped enlargement; connected with 

 this structure is a less muscular region, the ovejector, about 0.56 mm. 

 in length. The uteri are joined to this by a common stem which has 

 an average length of 0.41 mm. and a width of 0.05 mm. 



The eggs (fig. 21) are segmented in utero. The eggs are large, thin- 

 shelled, asymmetrically flattened, and have an average size of 0.087 by 

 0.192 mm. 



SPECIFIC DIAGNOSIS OF ALAEURIS LABICULA 



Principal characters of genus. Medium-sized oxyurids, the males 

 ranging from 3.11 to 3.46 mm. by 0.19 to 0.26 mm. and the females 

 from 5.57 to 6.80 mm. by 0.44 to 0.53 mm. Posterior extremity of fe- 

 male has a pointed tail about 0.72 mm, long; male with a short bluntly 

 rounded tail about 0.12 mm. long. No lateral or cervical alae; wide 

 caudal alae in male. Cephalic region indistinct ; three inconspicuous lips. 

 Mouth triangular. Eight cephalic papillae and two amphids. Papillae 

 arranged lateral to mouth, exhibiting bilateral symmetry, rather than 

 radial. Nerve ring encircles esophagus 0.18 mm. in male and 0.20 mm. 

 in female from anterior end. Excretory pore slightly prebulbar in both 

 sexes, varying from 1.08 to 1.31 mm. in the male and from 1.28 to 

 1.70 mm. in the female from anterior extremity. Esophagus ranges from 

 1.12 to 1.37 mm. in the male and from 1.34 to 1.42 mm. in the female 

 in length. 



Male: Three pairs genital papillae; precloacal papillae sessile and 

 on body eminences; adcloacal papillae on long peduncles; caudal pa- 

 pillae on short, stout peduncles, anterior to tip of tail. Cloacal lips con- 

 spicuous, resemble papillae-bearing stalks. Caudal alae wide. Spicule 

 sharply pointed, about 0.73 mm. long. Accessory piece well developed. 



