78 The Form of Insects 



connection with the ovipositor the poison glands 

 described above, so that the organ is modified into 

 a sting. The front pair of processes (belonging to 

 the eighth segment) are thick, hairy " feelers," while 

 the four processes of the ninth segment form the 

 actual sting, the outer pair fused together serving as 

 a support or sheath upon which the inner pair — 

 sharp, needle-like piercers with barbed tips — can be 

 pushed in or out. Each lancet is grooved, the 

 groove fitting on a rail-like projection of the sheath. 

 The lancets are also hollowed out along their inner 

 surfaces, so that a tube is formed between them 

 along which the poison flows (fig. 51). 



It is believed by many students that the front 



processes of the ovi- 

 positor are the modified 

 limbs of the eighth 

 abdominal segment, 

 ^ ^ ^ _ while the outer and 



Fig. 53. — Egg-Capsule of American Cock- . i • j 



roach. a. side view; i^. end view, muer hmd prOCeSSCS 

 The outline shows natural size. From rpnrptipnf nntpv anrJ 



Howard, Bull. 4 (n.s.) Div. Ent. U.S. represent outer ana 

 Dept. Agr. inner divisions of the 



limbs of the ninth segment (2). But it has been 

 shown by study of the growth of the parts in the 

 female cockroach (51), that the outer hind pair actu- 

 ally represent portions of the ninth sternite, since, 

 in the young insects, they carry at their tips stylets 

 similar to those of the male (p. 31), which disappear 

 in the female when the adult condition is reached. 

 Unless it be denied (50) that the stylets are the 

 reduced limbs of the ninth segment, neither pair 

 of hind processes in the ovipositor can represent 

 those limbs. It has been suggested that the inner 

 hind pair may really belong not to the ninth 

 but to the tenth segment (51, 58), of which 

 they might then be regarded as the limbs, the 



