220 INSECTA. 
ticulated palpi; the others inserted near the internal base of 
the preceding ones, resemble little linear laminze, which are 
pointed and crossed at their extremity like the mandibles of 
various Insects; they bear a greater similitude to the lancets 
of the sucker of the Diptera than to true mandibles(1). The 
head is also furnished with two large hemispherical, slightly 
pediculated, and granular eyes ; two almost filiform and short 
antenne, approximated at base on a common elevation, con- 
sisting of three joints, the two first of which are very short, 
and the third very long, and divided down to its origin into 
two long, compressed, lanceolate branches, laid one against 
the other. The ocelli are wanting. The form and divisions 
of the trunk are very similar to those of several Cicadariz, 
Psyllw, and Chrysides. ‘The abdomen is almost cylindrical, 
consists of eight or nine segments, and is terminated by pieces 
also analogous to those observed at the anus of the above men- 
tioned Hemiptera. The six legs are almost membranous, 
compressed, nearly equal, and terminated by filiform tarsi 
composed of four membranous joints with, as it were, vesi- 
cular extremities ; the last is somewhat larger than the others 
and presents no hooks. ‘The four anterior legs are closely 
approximated, and the two others thrown behind. ‘The space 
on the pectus comprised between these latter is very consi- 
derable, and divided by a longitudinal furrow. The poste- 
rior extremity of the metathorax is prolonged over the abdo- 
_men in the manner of a large scutellum. ‘The sides of that 
metathorax which give insertion to this last pair of legs are 
strongly dilated behind, and form a sort of inflated shield that 
defends the exterior and lateral base of the abdomen. 
These Insects, in their larve state, live between the ab- 
dominal scales of several species of Andrene and Wasps of 
the subgenus Polistes. They frisk about with a simultaneous 
motion of the wings and halteres. Although they appear to 
(1) According to Savigny, their mouth consists of a labrum, two mandibles, two 
maxillz, each bearing a very small uniarticulated palpus, and of a labium without 
palpi. 
