372 On Entomology. 
in the middle of tlieii' bodies, wliereby tbey are cut in tvvo parts, joined 
by a small ligature. " The descriptions and history of insects, con- 
stitute what scientific men term Entomology; derived from the Greek 
Entoma, insects, and logos, a discourse. Before this science was 
brought to any degree of perfection, it was generally supposed by 
most of the ancient philosophers, that maggots, flies, and insects of 
various kinds, were generated or bred from putrefactions substances. 
This belief originated in their having always found them existing in 
animal bodies, when in a state of decomposition ; the true fact has, 
ho\vever, latterly been estabhshed, that all insects come fi-om eggs as 
plants do from seed. This erroneous opinion was not merely confined 
to the ancients, but has been transmitted by tradition, from one gene- 
}ation to another ; and even in the present day, there are many to be 
found, who actually hold the opinion as fii-mly as ever, and these are 
not merely confined to persons wholly ignorant of the nature and 
economy of insects in general. There are many, however, in these 
enlightened days of science, who discover the absurdity of such opi- 
nions; but amongst these, are to be found individuals, who hold 
opinions almost equally as erroneous, — I mean that of insects, as cater- 
pillars, aphides, and indeed, most garden insects, being carried about 
by a dense copper-coloured cloud, erroneously called "the blight," 
and lighting on trees by millions, in the form of a shower called the 
honey dew. I find the eminent Dr. Good, in the third edition of his 
"Study of Medicine," vol. 1, p. 339, published in London, 1829, says 
"the atmosphere is freighted with myi-iads of insect eggs, that elude 
our senses," and that such eggs, when they meet with a proper bed, 
are hatched in a few hours, into perfect forms ; this, he concludes, is 
clear to any one, who has attended to the rapid and wonderful effects 
of what, in common language, is called a blight, upon plantations? 
and gardens, &c. &c. : and similar views to these are given in Hope's 
" Origin and Prospects of Man," quoted by Mr. Rennie, in page 
J 22 of your Register. If it be asked, if this is not the truth, how is 
it, that so many thousands appear in a garden in one day, vchen pre- 
viously none, or scarcely any, were before seen ? Mr. Rennie's an- 
swer, I would adopt as mine. — By the eggs being nearly all hatched 
at one time. It is impossible for the eggs to fly in the air after the 
manner they are said to do, were we to suppose them to be deposited 
loose, and at perfect liberty, which they are not, particularly the spe- 
cies found in gardens. 
As the study of the nature and economy of insects is persevered in, 
these errors will gradually give way : if we look back, only lo the 
17th century, we find opinions of philosophers, on the generations of 
reptiles, equally as fabulous ; but these have now disappeared. For 
