578 



INSECT A ORDER HYMENOPTERA. 



Fig. 5Q.Pelccinus 



politurator, Linn. 



Reduced. 



an inch across the expanded transparent wings, with a very small petiolated 



abdomen, so small that it hardly appears to belong to the insect ; and long 



sprawling legs, with very long black or red hind femora, much longer and 



thicker than the abdomen of the insect. Another genus of this family, 



Pdecinus (Latr.), is of a very different size and shape, but is 



not less remarkable. The species are black and shining, 



and measure an inch and a half across the rather long 



wings. The whole insect, however, is tfiree inches in 



length, on account of the great length of the joints of the 



abdomen, which looks like a telescope, except that the 



joints are of equal thickness. Such is the female. The 



male, which is very rarely seen, is much smaller, and has 



the abdomen very differently formed ; it is slender at the 



base, and gradually thickened into an oval club at the end. 



Here we see that instead of the ovipositor being lengthened 



in the female, the whole abdomen has been inordinately 



lengthened instead. This genus is not British, but is 



common in North America, and other parts of the world. 



We now come to the important section of the Hymenop- 

 tera Aculeata, which are not only more familiar 



insects than the Terebrantia, but have been much more 

 Stinging Hymen- s fc u <iied by entomologists, though not to anything like the 

 optera same extent as the two favourite orders of Coleoptera and 



(Aculeata). Lepidoptera. 



The first section, the Tubidifera, includes only one family, the Chrysididce, 

 or ruby-tailed wasps, which hold an intermediate place between the two great 

 sections of the Hymenoptera, being armed with a rudi- 

 Ruby-Tails mentary sting. They are small insects, generally expanding 

 (Chrysididce). less than an inch across the transparent wings. Their bodies 

 are very hard, and very strongly punctured, and when 

 alarmed, they double their bodies together, and sometimes roll themselves 

 up into a ball. Most of the species are of a brilliant 

 metallic green (more rarely blue), with the abdomen, 

 which is more or less smooth, at least towards the 

 tip, often purple or fiery-red towards the end. The 

 abdomen is usually composed of only three or four 

 segments visible above, and is more or less retractile 

 under the first, which is usually very much longer 

 than the others ; the last dorsal segment terminates 

 in a row of strong teeth, varying in size, form, and 

 number according to the species. The larvae are 

 parasitic in the nests of other Hymenoptera. We 

 have figured Stilbum amethystinum (Fabr.), a large species found in Asia and 

 Africa, which is sometimes blue and sometimes green. 



The first section of the true Hymenoptera Aculeata is that of the Heter- 

 ogyna, or ants. They are social insects, and consist of limited numbers of 

 winged males and females, and of numerous wingless and imper- 

 fectly developed females, called workers, or neuters. In 

 all Hymenoptera the female is the predominant sex, but 

 this is pre-eminently the case in the social species. When 

 the ants swarm, the males and females fly away and pair, 

 after which the great bulk of them perish. The females shed their wings, 



Fig. 60. RUBY-TAIL 



(Stilbum amethystinum). 



Nat. size. 



Ants 

 (Heterogyna). 



