ANATOMY. 595 



the super-coxal glands, are far larger in the nymphs 

 than in the images of the corresponding species, while 

 they have already attained the form and colour which 

 characterises those of the adult. 



Although the alimentary canal is so very similar in 

 the earlier and later stages the mode of the attachment 

 varies, as the canal of the nymphs is attached to the 

 skin by several muscular and membranous bands not 

 found in the adults. The reasons for this may possibly 

 be twofold ; firstly, that the soft skin of the nymph does 

 not afford the protection and firm points of anterior 

 and posterior attachment supplied by the hard, chiti- 

 nous integument of the adult; and, secondly, that any 

 support which the simple tracheae of the adult in most 

 genera are capable of giving is not available to the 

 nymphs. 



The Reproductive System. — The extent to which this 

 is developed naturally depends greatly upon the age of 

 the creature examined, but even in young specimens 

 some rudiments of the female internal sexual organs 

 may be found, while in the fully-grown nymphs the 

 secretive portions will have attained a very consider- 

 able degree of formation although the protrusible 

 organs more immediately connected with oviposition 

 do not appear to be present. The structure of those 

 parts that have been formed is, as might be anticipated, 

 similar to that in the adult, only the parts are of smaller 

 size and not yet functional ; thus, the central ovary is 

 present, and of considerable size, and plainly shows 

 the ova already formed, but without any sign of 

 impregnation or cell-division in them. The oviducts 

 and vagina are formed, but there is not any egg in 

 either, and the former are small in diameter, and 

 entirely without the chambers and the loop-hke folds 

 and turnings so conspicuous in the oviducts during the 

 reproductive period of life. The oviducts lead into an 

 unpaired vagina ; but I have not found the long exten- 

 sile corrugated ovipositor which is usually such a very 

 important organ of the adult female ; and I have not 



