68 
BRITISH APHIDES. 
devised, mainly on the basis of wing-venation, a classifi- 
cation of Aphides which has so far shown its excellence 
that it is the substratum of most of the modern adopted 
systems. 
In the year 1815 Kyber, the deacon of Eisenburgh, 
announced those important discoveries which threw 
increased light on the more special subject of the gene- 
ration and development of Aphides. His experiments 
entirely confirmed the earlier observations of Bonnet 
and He Geer, and gave a fresh impetus to what may be 
called the physiological side of these researches. 
Hitherto naturalists had chiefly bestowed their atten- 
tion on classification and description of species, but 
Kyber may be said to head a long list of anatomists 
and able microscopists who, by studying the internal 
economy of these minute insects, have illustrated and 
extended our knowledge of the remarkable changes 
which take place in their development and embryology. 
Only a few of these authors, however, can here be 
quoted, though many of their names are illustrious. 
Am,ongst these may be mentioned Duvau, who wrote, 
in the year 1825, on the anatomy of Aphis fabm ; and 
Dutrochet and Burmeister, who followed him in 1835. 
Charles Morren in 1836 explained at considerable 
length the internal organs of Aphis persicm, one of 
the peach Aphides, which has been since identified 
with Aphis dianthi, Schrank, and also by Professor 
Passerini with Bhopalosiphum persicce. 
Morren’ s treatise, in many respects, is excellent. 
He therein describes and figures the many-cham- 
bered ovary and adjuncts of the internal repro- 
ductive organs of Aphis in a more complete manner 
than had hitherto been done, but he fell into an 
error which, having been adopted by other physiolo- 
gists, has caused much keen criticism and discussion. 
After noticing the modifying effect of temperature 
upon these animals he says, Under ordinary circum- 
stances the female lays eggs when she has wings, 
and after union with the male, which is winged at the 
