9-2 CHARACTERS OF THE GENERA OF APHIS AND COCCUS. 
of Linne, and are arranged by modern Entomologists under four 
families :— 
4. Psyllidhe, Latr. containing the genera Psylla, Geoff. 
(Chermes, Linne ,) and Livia, Lat. 
5. Thripib.e, Steph. ? containing the genus Thrips of authors. 
6. ApHiDiE, Leach, containing the genera Aphis, Linne ; Erio- 
soma, Leach ; and Aleroydes, Lair. 
7. Cocciile, Leach, containing the genera Dorthesia, Bose, 
and Coccus, Linne. 
These genera may be made out with very little attention, by the 
following characters, and by the assistance of the figures referred to, 
which will nearly all be found in English works. I leave the detail 
of the injuries occasioned by them, and the remedies for those injuries, 
to your able pen. At the same time, I would suggest, that any 
remedy applied for the destruction of these pests, can only prove 
effectual when the young are just hatched, and leave the mother ; 
for nothing short of scraping them off the plants will avail, after the 
females have settled for life.’’ 
I. Fam. Psyllhle, Lat. Ordo Hemiptera, Linne. 
Antennae, with ten or eleven joints; legs formed for leaping. 
Both sexes with wings. 
1. Gen. Psylla, Geoff. ; Chermes, Linne. 
Snout (rostrum) bent under the breast; antennee longer 
than the thorax ; wings four, deflexed ; thorax gibbous ; 
feet formed for walking and leaping. 
Ex. P. Buxi, Linne. Wood's Illustrations of the Linnean 
Genera of Insects, vol. i. p. 114, pi. XL. 
Twenty-four indigenous species have been described or 
indicated in various works; but this, doubtless, falls very 
short of their actual number. 
2. Gen. Livia, Latr. 
Antennee shorter than the thorax, the base much thickened 
even to the middle; thorax with the anterior segment 
transverse, straight. 
Ex. L. Juncorum, Latr. Sam. Ent. Comp. pi. V, f. 11. 
Inhabits rushes. But one British species known. 
V. Fam. Thripida:, Steph . ? 
Antennae eight-jointed. 
1. Gen. Thrips, Linne. 
Snout (rostrum) secreted within the mouth; antennae the 
length of the thorax; body linear; abdomen inclining 
upwards; wings four, straight, long, incumbent on the 
back, narrower than the body, slightly crossing. 
