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development as commencing in the fatty tissue of the first larva, 
from which tissue small portions are separated. These, at first 
grouped together, become afterwards detached in single por- 
tions ; their fatty contents become granular ; and from these 
vitelline cells and a germ-cell are formed, which go through 
rapid development. The Professor’s observations led him fur- 
ther to the conclusion that the fatty tissue of the larva is itself 
a residue of the original yolk of the egg of the summer insect, 
and is therefore endowed with formative powers and a speciality 
of function, in virtue of which germs are produced, which un- 
dergo rapid transformation, and thus play the part of pseudova, 
as observed in other insects. If, however, this fatty tissue be 
an actual residue of vitelline matter, it is obviously misnamed. 
2. Dr. Meinert, of Copenhagen, was the next to discover the 
Cecedomyia. larva (under the back of a beech tree), and to watch 
the larval propagation. After following its final metamorphosis 
into an insect, he was enabled to describe and name it, and he de- 
signates it Miastor Metraloas. He also assents to Wagner’s 
opinion respecting the origin of the larval germ from the fatty 
tissue, and agrees in considering this tissue as part of the 
original formative material derived from the insect egg. 
3. Professor Pagenstecher, of Heidelberg, next took up the 
investigation. This observer met with similar but smaller larvae 
(belonging to another species) in the musty refuse of beet-root 
that had been used in a sugar manufactory. This refuse matter 
(after extraction of sugar), which was in a state of decompo- 
sition, contained abundance of other insect life (larvae of Cole- 
optera, Myriopoda, Anguillulae, Podura, &c.), and was sent to 
him for examination, because cattle fed with it became diseased. 
According to this observer, the fatty tissue has no direct rela- 
tion to the germs of the larval broods. These appeared to be, and 
are spoken of by him as true “ ova.” The smallest observed 
were y^-th inch in length, increasing gradually to J F th inch. 
He explains the great increase of bulk which the ova gain 
daring development as the result of ordinary nutritive imbibi- 
tion, and not of any absorption of the fatty tissue, which, how- 
ever, disappears gradually, as the changes of development go on. 
The “ ova ” (or germs) were found in their earliest stage chiefly in 
the neighbourhood of the posterior segments of the body in the 
subcutaneous cellular layer. As they grew larger, they moved 
forward, and were lodged in the free spaces between the viscera. 
The ova at this time consist of a spheroid mass, whose outer 
circle is formed by a layer of clear globules, within which is an 
inner mass, composed of granular particles, interspersed with 
vacuoles. There is no organic union with the fatty tissue, the 
ova lying free in the general cavity (or visceral interspaces). 
The embryonal masses described by Wagner have, says Pagen- 
