580 



ZOOLOGY 



SECT. 



peri 



seg 



into the anterior end of the ejaculatory duct (duct, ej.), an un- 

 paired tube with muscular walls opening on the exterior imme- 

 diately below the amis. Around the genital aperture are a series 

 of chitinous processes, the gonapopliyses, which subserve copulation. 

 In the female there are two groups of ovarian tubes or ovarioles, 

 each group or ovary (Fig. 463, ov.) consisting of eight. The 



tubules of each group are 

 united together anteriorly, 

 where they are connected by 

 a ligament to the dorsal 

 body-wall. Posteriorly each 

 group is connected with a 

 lateral oviduct (od.). Each 

 ovarian tube has a beaded 

 appearance, owing to its con- 

 taining a row of ova, which 

 increase in size posteriorly. 

 The two oviducts unite to 

 open by a median aperture 

 on the sternal surface of the 

 eighth segment of the abdo- 

 men. A pair of unsymmetri- 

 cal sacs opening together in 

 the middle of the sternum 

 of the ninth segment con- 

 stitute the spermathecca or 

 receptaculum seminis. A pair 

 of ramifying glandular tu- 

 bules, the collctcrial glands 

 (coll. yld.), open behind the 

 spermatheca, A series of 

 chitinous gonapo'pliyses, which 

 aid in depositing the eggs, 

 are situated between the 

 female genital aperture and 

 the anus. 



3'k.c Development. The eggs 



are enclosed sixteen together 

 in horny capsules, the sub- 

 stance of which is secreted by 

 the colleterial glands. They 

 are laterally compressed, con- 

 cave on one side (the future ventral side), convex on the other (the 

 future dorsal side). Each egg is enclosed in a thin egg-shell, or 

 chorion, with several small openings. The nucleus, originally plainly 

 distinguishable in the ovarian ovum, is no longer visible in the 

 egg when laid, owing to the accumulation of food-yolk. It is to be 



blast 



blast 



FIG. 4G4. A D, successive stages in the seg- 

 mentation of tin' ovum of an Insect: i>l<ixt. 

 blastoderm ; pen. peripheral protoplasm ; seg. 

 segmentation culls ; ///. yolk : ///. <: yolk-ivlN. 

 (From Korschelt and Heider, after Blochmann.) 



