10 
PROCEEDINGS OF SOCIETIES. 
favourite explanation, in cases of imperfect and difficult observation, so long as 
the improvement of optical appliances, and the growing inductions of experience 
had not prepared the way for Harvey's proverb, “ Omnia exovo.’’ The invention 
of the microscope opened, as it were, a new world to man’s contemplation, and 
revealed the secret inscription, *‘Deus maximus in minimis.” Creatures which 
escape our senses by their minuteness, or provoke our disgust by their appear¬ 
ance or habits, are yet as points and letters in the page of nature, traced by the 
finger of its Maker there. And man, who is but dust, and returns to dust, may 
learn a lesson from the study of the dust itself that cleaves to the sole of his foot. 
The ingenious Hooke, in his Micrographia, a.d. 1667, gave the first good figure 
of the flea, which long continued to be copied into dictionaries and text-books, as 
the best extant. He observed “ the quick, round black eye, and the cavity behind 
it, in which seems to move to and fro a certain thin film, beset with many small 
transparent hairs,”* * § which he suspected might be the ear; an opinion not dis¬ 
carded for many years after. The celebrated Leeuwenhoek first solved the 
problem bequeathed by Aristotle, and proved that the flea undergoes a meta¬ 
morphosis,! even as the butterfly, whose wonderful history has long afforded a 
text to the poet and the theologian. But his brief indication of the fact was 
first fully illustrated by a communication to the Royal Society of London of the 
observations of Dr. Jacinto Cestoni, of Florence, accompanied with figures of 
the different stages of the flea’s development.J These observations leave little 
to be desired, accurately determining many points which at a very recent period 
have continued to be the subject of debate, or have been given as novel facts. 
The figure of the larva, after Cestoni’s drawing, though tolerably faithful in the 
main, gave exaggerated length to the antennae and the anal hooks. The pro¬ 
portions of these were better expressed by Roesel,§ although he fell into some 
trifling errors (which we may have to notice again), in consequence, probably, of 
the imperfect defining power of the microscope, the excellence of which his 
editor, Kleemann, takes occasion to commend on the ground of some of those 
very errors. Frisch, Degeer, and others, also observed the transformations of 
the flea, and Degeer distinguished a changeable soft protuberance on the under¬ 
side of the head of the larva, as to which we are not even yet quite clear.|| Up 
to this period, although the structure of the mouth in its outward complex form 
had been pretty well represented, its real composition was little understood, and 
the projecting four-jointed manillary palpi were commonly taken for antennae, 
in the absence of any other organs to represent these in the usual place. 
Lutreille, with clear judgment and characteristic modesty, suggested the true 
relations of the parts,which Savigny** fully verified twenty years afterwards 
by those careful dissections, which established on a sure basis the important 
principle of the homology of the parts of the mouth in all insects, first suggested 
by Uliger,ff embraced by the most philosophical entomologists of later times, 
and well set forth in its extended application to the whole of the AnnulataJJ by 
Erichson, lately snatched away from us—alas! too soon for the cause of science 
and sound criticism. The supposed antennae being proved to belong to the 
mouth, it remained to confirm Latreille’s opinion of the presence of antennae in 
the problematical organs behind the eye ; and this task was satisfactorily per¬ 
formed by Curtis, who first demonstrated the labial palpi existing in the 
* Micrographia, p. 210. 
f Opera Tom. 1, Epist. 10. a.d. 1687.—Tom. 4. Epist. Phys. 37. a.d. 1719. 
X Philosophical Transactions a.d. 1699. p. 42, 43. 
§ Insekten Belustigungen Bd. 2. Muecken u. s. w. Taf. 2, fig. 7 
|| Memoires etc. Tome 7, ch. 1, pi. 1, fig 4. 
Histoire Naturelle des Insectes Tome 2, p. 335.—Tome 14, p. 405. 
** Memoires sur les Animaux sans vertebres i. 27. 
ft Kaefer Preussens, Vorrede xxi. 9. 
jf Ueber Zoologische charactere der Insekten u. s. w. 
