540 



INSECTA. 



B. 



easier movement. They have larger eyes and antennae, and their 

 colours are brighter and more striking. When there is a pronounced 

 dimorphism the females are apterous, and their form approximates to 

 that of the larva (Coccidce, Psychidce, Strepsiptera, Lampijris), while 

 the males are provided with wings. 



The female generative organs are composed of paired ovaries and 

 oviducts, the unpaired oviduct, the vagina and the external genital 

 apparatus. The ovaries are elongated tubes, in which the eggs 

 originate. The ova lie one behind another in a single row like a 

 string of pearls, increasing in size from the blind end to the opening 



into the oviducts (fig. 91, a). The 

 arrangement of these ovarian 

 tubes presents extraordinary 

 variations, and there thus ori- 

 ginates a great number of dif- 

 ferent forms of ovary, which 

 have been described principally 

 in the beetles by Stein. The 

 number of the ovarian tubes 

 also varies exceedingly, being 

 least in some Rlyncliota, and 

 then in the butterflies, the 

 latter having on each side only 

 four very long ovarian tubes, 

 which are many times folded 

 (tig. 448). At their lower ends 

 the ovarian tubes on either side 

 open into the dilated commence- 

 ment of the oviduct, which joins 

 with that of the other side to 

 form a median oviduct. The 

 lower end of the latter repre- 

 sents the vagina, and often 

 receives, near the genital aperture, the ducts of special cement and 

 sebaceous glands (yknulithe sebacece), the secretion of which is used to 

 surround and fasten the eggs which are about to be laid. In 

 addition to these glands, the unpaired efferent duct of the genital 

 apparatus is very commonly furnished with one or several usually 

 stalked receptacula seminis (fig. 449), in which the semen, often 

 introduced in the form of spermatophores, retains its fertilizing 

 properties for a long time, sometimes for years, under the in- 



FIG. 448. Female sexual organs of 

 vrtictf (after Stein). Or, The ovarian tubes 

 cut off; Sc, receptaculum seminis ;m<l 

 accessory glands; I',,, vagina; Sc, bursa 

 copulatrix with duct leading- to the oviduct ; 

 Di; glandular appendage; Dr', glandula? 

 sebacea? ; S, rectum. 



