418 MODERN CLASSIFICATION OF INSECTS. 
Thripidee, ordinarily regarded as portions of this order, we have seen 
possess a mandibulated palpigerous mouth, and hence they have been 
removed to the neighbourhood of the Orthoptera. In like manner, 
amongst the Aphides we find some species destitute of wings; and 
even amongst the Cicadz of Linnzus, some of the species have the 
fore wings as leathery as in many of the Coleoptera: but it is in the 
Coccide that we find the greatest aberrations, for here, at least in 
the typical species, the alary and metamorphotic characters are lost, 
the only tie being that of the suctorial mouth, and even its parts are 
widely different from those of the true types of the order; whilst the 
dipterous halterated condition of the males destitute of a mouth, and at 
the same time undergoing an inactive metamorphosis, bespeaks as com- 
plete a want of conformity with the order as can be produced — suffi- 
cient, indeed, in the opinions of some authors to raise them into a distinct 
order ; De Geer and his commentator Retzius having separated them 
under the name of Proboscidea, and Laporte under that of Phaulop- 
teres, the last-named author having also separated the Aphides as 
another distinct order, under the name Gynaptéres. (tudes Entomol. 
p. 7.) I think it however more advisable, in the present state of the 
science, to retain these two groups as portions of the order. 
In this extent we accordingly find the order divided by Latreille 
into four families, in his Genera; namely, Cicadarie, Psyllide, 
Aphidii (including Thrips), and Gallinsecta (Coccus). In his latew 
works, however (Régne Animal, 2d ed. tom. v. p. 224.), we find the 
Psyllidee reduced to a division of the Aphidii, whilst Burmeister, who 
adopts the views of Nitzsch as to the relations existing between the 
Pediculi and the Fabrician Rhyngota, or haustellated Hemiptera of 
Linneus, and likewise introduces the Heteroptera into the order, for 
which he retains the name of Rhyngota (rejecting that of Linneus ; 
the mouth and not the wings being his primary character), divides it 
into six stirpes : Pediculina, Coccina, Phytophthires (including two sub- 
divisions, Aphidina and Psyllodes), Cicadina, Hydrocores, and Geo- 
cores. Of these, the second, third, and fourth stirpes constitute the 
present order. 
Mr. Stephens, on the other hand, divides the order into seven primary 
families: Cicadiide, Fulgoridze, Cercopide, Psyllide, Thripidae, Aphide, 
and Coccide. Of these, the first three are of much less relative value 
than the rest ; the fourth is too closely allied to the Aphidz to be con- 
sidered as a distinct primary group, and the fifth must be removed 
from the order. 
