TIIM OKICUN OF FLOWERS 



191 



regarded an adaptations to llower-viHitin^', with, a i'uw inolated 

 ex(!(iptioiiH, ol' whicli one will lio iiiontioned later. TWh is intelligible 

 enough, for tlu) Lutterlly haw nothing nioi'o to Heek I'roni the flower 

 beyond i'ood for itiscili"; it dooH not carry stores i'or offspring. 



Tlu! bo(!H, how(!Vor, do this, and iieeordingly we find that in them 

 the adaptations to flower-visiting are not confined to the mouth- 

 parts. 



Ah i'ar as we can judge now, the flower-visiting bees are 

 descended from insects which I'osumbled the modern burrowing- 

 wasps. Among these the I'omales themselves live on nectar and 

 pollen, and build eulLs in holes in the ground, and i'ued their brood. 

 They do not I'c^od them on lioney, however, 

 but oil animals -on caturpilhirs, grass- 

 hoppers, and othur insects, which they 

 kill by a sting in tho abdomen, or often 

 only paralyse, so that thu victim is 

 brought into the ccdls of the nost aUve 

 but dcronccluss, and remains alive until 

 the young larva of tho wasp, which 

 emerges from the egg, sets to work to 

 devour it. 



Before I go on to (explain the origin 

 of the sucking [u-oboscis of tho bci! from 

 tho biting mouth-parts of the primitive 

 insects 1 must first brioHy consider tho 

 latter. 



The biting inouth-];)ai'ts of beetles, 

 Neuroptora, and Orthoptera (Fig. 4^), 

 consist of throo paii-s of jaws, of which 

 tho first, the mandibles (md), are simply similar dotaUud'partr 

 powerful pincers for seizing and tearing 



or chewing tho food. They havo no part in the development of the 

 suctorial apparatus i^ither in bees or in butterllios, so they may be left 

 out of account. The two other pairs of jaws, tho first and second 

 mnxillaj {mx^ and mx^), are constructed exactly on the same type, 

 having a jointod basal portion (si) bearing two lobes, an external {le) 

 and an internal (li), and a fook'r or palp, usually with several joints, 

 ilirected outwards from tho lobes {/>in, and |i). Tho second pair of 

 maxilhe (inM-) differs from the first chiefly in this, that the com- 

 ponents of the pair meet in the median line of the body, and fuse 

 more or loss to form the so-callod ' under lip ' or labium.^ In the 

 example given, tho cockroach {Ferli>lancta urlentalin), this fusion 



N 'i 



Fki. 48. Moutli-parts of tho 

 Oooki'oaoh {I'cri/ilantita orientalis), 

 iiftur R. Ilc'ilwif,'. la, uppoi- lip 

 or labruni. md, mandiblos. jjia;', 

 lii'nt niaxilloB, with c, oardo, st, 

 stipes, li, internal lobe or laoinia, 

 le, Gxtornal lobo or galea, and pm, 

 tho maxillary palp, mx', tho 

 labium or second maxillio, with 



