MR. LUBBOCK ON THE THYSANURA. 443 
freshly killed insects glitters like threads of quicksilver ; and howover absurd it may 
sound, I consider the inside of an insect, with its beautiful and rich tracery of glittering 
tubules, to be one of the loveliest objects in nature. In searching, therefore, for 
tracheae we are very much assisted by the presence of the air ; and while in preserved 
specimens these organs are not 
specimens they are generally very conspicuous. 
I have not yet discovered in Papirius any other organs of respiration ; but, comidcrin 
easy to trace, at least towards their extremities, in fro li 
quite poss 
how soon these animals dry up if placed in a dry atmosphere, it seems 
that they may respire through the general surface of the skin. 
Female Generative Organs. — The ovaries of Smynthurus are very simple. From th< 
delicacy of their membranous envelope, it is not very easy to extract them entire; but 
the best wav is to make a section of the animal from the back at the anterior part of 
the cephalothorax, to the base of the spring : in this case, the ovaries will generally be 
found uninjured, and may be separated from the other organs without very much diffi- 
culty. They consist of a single, short and broad egg-tube on each side, and unite 
posteriorly to form a narrow vagina about -003125" in length. Having found i1 impossible 
to remove the skin in such a manner as to expose the ovaries in si/tt. and as the me 
above described destroys, of course, the natural position of the organs, I am nnabl< 
to say much as to the usual position of the ovaries. They did not appear, however, 
to pass directly forwards, but seemed rather to curve round from the point of attach- 
ment to the vagina so as to lie rather in the posterior part of the body. They were, 1 
think, on the dorsal side of the intestinal canal ; but this point I unfortunately forgot 
to note at the time. 
M. Nicolet was unsuccessful in his search for the organs of generation. " Je l'ai deja 
dit," he says, " les difficulty que l'extreme petitesse de ces insectes oppose a la dissection, 
rendant fort difficile l'etude de leur organisation interieure, qui peut-etre restera 
longtemp 
le hasard seul, en rendant un observateur temoin d un accoupl. 
nient, pourra faire deeouvrir leurs organes genitaux, mais un pareil hasard est dime 
pre\ 
I quote this sentence as an excuse for the numerous details, in the anatomy 
of Smynthurus, which I have left unascertained; many of which, however, want of time 
alone has prevented me from making out. I may add that the small size of Smynthurus 
gave me less difficulty than its curious form and the extreme delicacy of its internal 
organs. By opening the animal, however, as above mentioned, I was able several 
times to make out the vagina above described, and also to trace it to the vulva, which, 
with the anus, opens into a common cloaca at the posterior end of the body ; this, 
however, from the great development of the segment bearing the spring, is thrown 
apparently on to the dorsal surface. 
The only accessory organs which I could find were two small, glandular, rounded bodies 
attached to the vagina close to its orifice. They were -0055" in width, and shaped like a 
kidney, with the convex side in front. On the other side of each, that is to say near the 
vulva, is a dark-brown rounded mass, about -003" in diameter. Beyond their relative 
position, I did not make out the relation which these organs bore to one another or 
to the vaeina. 
