INTRODUCTION. 



15 



erro-a rrive rise to new individuals without the intervention of male 

 (parthenogenesis). 



The reproductive organs of insects may, according to instructions 

 given in certain works on microscopy, be carefully dissected from the 

 abdomen, but the accom- 

 panying figures, together with 

 the explanation, convey a 

 very good idea of the repro- 

 ductive organs of insects. 

 The accompanying figures 

 and explanation have been 

 selected because they are not 

 only large insects, but arboreal 

 in their habits. It may also 

 be noted that, as regards 

 insects, the hive bee has been 

 carefully worked out in this 

 respect, so that reference to 

 any of the more important 

 works on the bee would be 

 found very helpful. 



Genital organs. " The 

 female, as in other Arthro- 

 poda, possesses a pair of 

 ovaries. Each consists of a 

 varying number of tubules 

 (ovarioles), which usually ex- 

 tend like fingers from the 

 anterior end of the oviduct. 

 Each ovariole is surrounded 

 by a thin membrane, and is 

 immature anteriorly, consist- 

 ing of small homogeneous 

 cells ; farther back there are 

 larger cells, young ova, lying 

 in the middle of the tube, and surrounded by smaller cells, which 

 provide them with nutriment, and also secrete the shell (chorion) 

 for the fully developed egg. The mature ova occupy the posterior 

 ends of the ovarioles, and pass thence into the oviduct. When an 



Fig. IS. Food canal of cockroach. 



salivary glands and reservoir ; c, crop (the gizzard 

 below it); cos, crecal tubes (below them the 

 stomach); k, kidney tubes; i, intestine; r, rec- 

 tum. Twice natural size. (From 'The Cockroach,' 

 by Miall and Denny.) 



