282 PRACTICAL LESSONS IN SCIENCE. 



this immense group of insects, numbering some 80,000 species. 

 They are properly called beetles, not bugs, which is the name ap- 

 plied to the Hemiptera. 



The Hymenoptera. This group includes the bees, wasps and 

 ants. They have mouth parts adapted to biting and licking; 

 the head is large with three ocelli and large compound eyes. 

 There are two pairs of membranous wings fitted for prolonged 

 flight. The body is compact, of about average size, the nervous 

 system complicated and highly developed, so that in the matter 

 of intelligence and capacity for work we would expect this group 

 to stand easily at the head of the insect world. In the female 

 the abdomen ends in an ovipositor, or more commonly with a 

 sting and its associate poison glands. The leaf-wasps, wood- 

 wasps, gall wasps, ichneumen flies and others have ovipositors 

 and deposit their eggs in wood, leaves or other vegetable struct- 

 ures, some making quite deep excavations. 



The Formicidae or Ants, live together in communities, which 

 contain winged males and females, but are composed mainly of 

 wingless individuals called workers. The female has a sting and 

 poison gland, and the workers, supposed to be aborted females, 

 also have poison glands. The dwellings of ant communities con- 

 sist of passages and cavities in rotten wood or in the earth. 

 Customs vary in different communities, but the following is per- 

 haps the history of an average colony : Some time during the 

 summer the males and females reach the adult size; soon after- 

 ward they take the marriage flight. The males soon die, and the 

 females attend to the matter of raising their brood or founding 

 new colonies. In general there seems to be a tendency among the 

 young females to form colonies by themselves or with a body of 

 workers, but usually females enough are forcibly retained by the 

 workers of the original colony to continue it as a strong commu- 

 nity. The fertilized eggs are exposed to the morning sun, covered 

 from its heat during midday and removed from the influence of 

 damp and cold at night. The grub is treated in the same way, 

 and besides is fed by the nurse or female with a liquid disgorged 

 from the stomach. After passing into the pupa state they are still 



