148 SCHOOL ENTOMOLOGY 



bumble-bees in size and general appearance. Other bees 

 dig burrows in the ground, mainly in the sides of steep 

 banks. Such bees are solitary, in the strict sense of the 

 term, but frequently a bank will contain the burrows of 

 hundreds of these bees. Some of the miners form colo- 

 nies, all members of which use one entrance to the nests, 

 the nests being separate for each individual. Professor 

 Comstock likens the abodes of the two classes of miners 

 here mentioned to villages of many separate houses and 

 to city apartment houses with many dwellings in one 

 house. There are bees which have a semi-parasitic habit, 

 the females laying their eggs in the nests of other bees 

 and leaving them to be cared for by the " hosts." These 

 are termed "guest-bees" or inquilines. 



While we are accustomed to consider the economic 

 status of insects from the standpoint of the damage they 

 may do, the consideration of the fact that the bees are 

 indispensable to the production of many of our most val- 

 uable crops, should show us that insects, as a whole, are 

 indispensable and make us more tolerant of the injurious 

 species, if it be necessary that we have both kinds to have 

 the beneficial ones. 



98. True Wasps. Wasps (Vespoidea) are distinguished 

 from bees by the tarsi, which are not fitted for carrying 

 pollen, and by the more slender forms of most of the spe- 

 cies. They are separated from the next group (digger-wasps) 

 by the resting position of the wings. In the true wasps 

 the front wings at rest have one longitudinal fan-like fold; 

 in the digger-wasps the front wings are not folded. 



Some of the true wasps are social and resemble the 

 bumble-bees almost exactly in their social organization. 

 All the insects commonly called Hornets and Yellow- 

 jackets are true wasps. 



