e50 
BRITISH APHIDES. 
servir a THistoire des Insectes/ and his ‘ CEuvres d’His- 
toire Naturelle et de Philosophie,’ published at Keu- 
chatel in 1779. There is no cause for wonder that 
the publication of the novel and unexpected facts he 
brought to light— particularly those connected with 
the parthenogenesis of Aphides— should have provoked 
discussion and much opposition. Evidence of this 
opposition is to be found in the heap of voluminous 
literature extant, the production of which has, almost 
without cessation, increased to the present day, and 
even yet shows no sign of abatement. Notwithstanding 
the lapse of time, a perusal of Bonnet’s work on this 
family will repay the reader of to-day. Indeed, we 
must be struck by the circumstance that to his address 
and concentrated attention we are mainly indebted for 
some of the most important points relating to their 
life-history. 
A short sketch of Bonnet’s observations may not 
be considered uninteresting. 
Early in his treatise he points out the resemblance 
that ^Hes pucerons^^ proper bear to ^Hes faux pucerons^^ 
of Beaumur, who had separated them into a group by 
themselves under the name of ‘‘ les moucherons sauteurs,^^ 
alluding to their leaping habits. This group consists 
of the Psyllidce, of which Beaumur describes two species, 
viz. that infesting the box- tree {Buxus sempervirens), 
and that which, in France, appears to attack the fig- 
tree {Ficus), Bonnet divides his pucerons proper j 
into two principal sections, viz. those which possess 
cornicles and those which want the same. He remarks 
that the family is rich in species, and that the plants ' 
attacked by them are extremely numerous. He states, 
not only are there many kinds which feed on leaves, 
on flowers, and on the twigs of trees, but there are 
those which form companies under ground, and attach 
themselves to roots. Bemarking on the large swellings 
not unfrequently found on the elm-tree, {^^ grosses vessies^')^ 
he points out the difierences between these distortions 
and those formed by ordinary gall-insects. He after- 
