616 
ME. LUBBOCK ON THE GENEEATm OEG-ANS, AND 
meter. I only met with one specimen carrying young. The latter were fully developed, 
and of the mature form, but still incapable of motion. They were much larger th&n 
the eggs. 
On dissecting these five specimens I was astonished to find in them no trace of an 
ovary, nor of a testis, but instead, and in the same position, I found a large organ 
(Plate XVII. fig. 30) consisting of thirty short cylindrical cseca with parallel walls. 
In front the organ passes into two large bags ; and from the anterior end of each of 
these, rises a short duct. I did not trace these ducts to their extremity ; but they pro- 
bably open near to one another. This seemed to happen close to, if not at the place, 
where the vulva occurs in ordinary specimens. The organ contains oil-like vesicles, 
which vary in size up to -g-^^oths of an inch ; the usual size, however, is from ^y%^ths 
to s-cuTol^s of an mch, and the larger ones contain daughter vesicles. It would appear 
that this remarkable organ must secrete nourishment for the embryos, in which way we 
may account for their great increase in size before leaving the mother. I have not, 
indeed, evidence sufficient to prove this ; but it would not be altogether without analogy, 
since Leuckaet has discovered in the viviparous Diptera a branched organ which secretes 
a substance to serve as food for the young during its stay in the uterus. 
Whereas, however, this branched organ is present in all the females of the vmparous 
Diptera, I have never found the sacculated organ of Clielifer except in the egg-bearing 
specimens, although in the months of September, October, and November I dissected a 
great many females, and particularly sought to find the structure in question. 
All the specimens examined by me were found within a few feet of one another, 
under some planks which were lying on a hot-bed in our kitchen-garden, and I noticed 
no external difference between the egg-bearing specimens with the sacculated organ and 
the ordinary males and females. Unfortunately, however, my attention was not at first 
directed to this point ; and when after only a fortnight’s interval I returned to my Che- 
lifers, no more case-bearing specimens were to be found, though in the last fortnight of 
September I looked over more than a hundred specimens in hopes of finding some. 
Moreover, the females examined during this time and up to the beginning of November, 
all contained eggs developing in the ovary, as above described. It is also worthy of 
notice that, whereas the ovary always contained from thirty-five to forty eggs in one stage 
of development, the number of eggs in each egg-case Avas only seventeen or eighteen, as 
before mentioned. 
It may naturally be asked to what organ in the ordinary females this sacculated 
structure corresponds ; and to this question I can give no satisfactory answer. It seems 
most probable, however, that it is a modification of the ovary. The form and position 
of these two organs is very similar ; and there are two ducts, as in the testis; moreoA'er, 
the egg-follicles of the one are someAvhat similar in size and shape, and not very different 
in number, from the caeca of the sacculated organ. In one instance also I found the 
ovarian folhcles with numerous small greenish oil-globules, while in the regular course 
of egg-development they contain large, dark, and very bright ones. In this state the ovary 
