CLASS-BOOK OF ZOOLOGY. 143 



QUESTIONS ON SECT. XXXVI. 



588. By what are the Net-winged Insects distinguished? Name some 

 of them. 



589. Where are Dragon-flies seen, and on what do they feed? 



590. Where is the abode of its larva, and how long does it dwell 

 there ? 



591. Why may they be considered useful? 



592. Describe the Day-fly. 



593. Why was it so called ? 



594. How is it indemnified for the shortness of its life ? 



595. Where, when, and in what numbers is it seen? 



596. What singular fact is mentioned with regard to it ? 



597. Describe the Ant-lion. 



598. Describe its larva. 



599. In what maimer does it catch other insects ? 



SECTION XXXVII. 



5th Order — Vein-winged Insects : (Hymenoptera.) 



§ 600. The Vein-winged Insects, such as Wasps, Bees, 

 Ants, etc., are distinguished by having four membranous 

 wings, with few but strong veins, and by generally being 

 shorter and smaller than the foregoing Orders. 



\ 601. Most of these Insects are armed with a sting, 

 and occasionally with venom, which they infuse into the 

 puncture made by their sting. 



§ 602. Their larvae are mostly Maggots ; that is, they 

 have no feet, as, for instance, those of Bees ; but some of 

 them, like Caterpillars, are provided with twenty feet, as 

 the Tenthredo. 



\ 603. The Vein-winged Insects answer several im- 

 portant purposes. Some of them produce honey and 

 wax, as the Bees ; others destroy millions of noxious in- 

 sects, by depositing their eggs in their larva? ; and others 

 aid the productive power of plants, by mixing the flower- 

 dust of blossoms, which, accidentally clinging to their 

 feet, is conveyed from one flower to another. 



\ 604. Oak-balls, and the excrescences on wild-roses, 



