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 t ^ e 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 l *frSK -ally the second abdominal seg- 



maxilla of larva; i.mx., maxilla of adult; rnent. 



/./., labium of larva; i.H., labium of adult. Thg mout h- pa rts are variously 



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. 



