460 
Saw-flies, Gall-flies, Ichneumons, 
as are also the females of the Mutillid wasps and a few other exceptional 
forms. In many Hymenoptera (shown 
well in the honey-bee) the fore 
(costal) margin of the hind wings 
bears a series of small but strong 
recurved hooks which, when the 
wings are outspread, fit snugly over 
a ridge along the hind margin of the 
fore wing, the two wings of each side 
being thus fastened together so as to 
move synchronously. A structural 
characteristic not readily made out 
but of much morphological impor- 
tance is the complete fusion of the 
Fig. 646.—Lateral aspect of head of full- true first abdominal segment with 
grown larva of honey-bee which has been the thoracic mass, SO that the small 
cleared so as to show the forming adult head ... ■, , 
within, ih., head of adult; i.e., compound articulating segment between what 
eye of adult; lc., body-wall of larval head; are called thorax and abdomen is 
i ant.. antenna of adult; l.md.. mandible of „ 1 vj • 1 
larva; i.md., mandible of adult; l.mx., really the second abdominal seg- 
maxilla of larva; i.mx., maxilla of adult; ment. 
l.li., labium of larva; i.li., labium of adult. The mouth _ parts are various l y 
modified, but usually are fitted for both biting and sucking (or lapping). 
This is arranged for by having the maxillae and 
labium more or less elongate and forming a sort 
of proboscis for taking up liquids, while the man¬ 
dibles always retain their short, strong, toothed, 
jaw-like character. The mandibles of the honey¬ 
bee are modified into admirable little “trowels’’ 
for moulding wax and propolis. The females 
throughout the order are provided either with a 
saw-like or boring or pricking ovipositor, or with 
the same parts modified to be a sting. The sting 
is possessed by the wasps, bees, and ants (rudi¬ 
mentary in many ants), on which account these 
groups are often referred to collectively as the 
aculeate Hymenoptera. The sting of the honey¬ 
bee is shown in Fig. 650 and is a well-developed 
example of this characteristic hymenopterous 
weapon of defence and offence. The barb-tipped 
darts (d) extend down through the sheath (s) and 
.are controlled by the chitinous bars called levers 
(/). The poison produced in the poison-gland (p.gl.) and stored in the 
Fig. 647.—Mouth-parts of 
mud-wasp, with mandible 
and maxilla of right side 
removed, md., mandible; 
mx., maxilla; mx.l., max¬ 
illary lobe; mx.p., maxil¬ 
lary palpus; li., labium; 
m., mentum of labium; 
pg., paraglossa; gl., glossa; 
li.p., labial palpus. 
