374 



CHARACTERS OF INVERTEBRATE ANIMALS 



of paper formed by working up bark and decayed wood to a sort 

 of pulp. Another and larger social wasp is the Common Hornet 

 ( Vespa crabro], in which the front part of the body is of a reddish 

 colour. Of solitary species the Mud- Wasps (Odynerus parietum 

 and others) may be mentioned, which construct their cells of mud 



in the crevices of walls, the 

 hollow stems of plants, and 

 other places. 



Bees, like Wasps, include 

 social and solitary species, the 

 Hive- Bee (Apis mellificd) fur- 

 nishing a good example of the 

 former sort, that also includes 

 the Humble- Bee (Bombus ter- 

 restris] (fig. 227), which makes 

 its nests in the ground. In 

 solitary bees the labium is 

 much shorter than in the 

 Hive- Bee. They belong to 

 numerous genera, and include Leaf-Cutter Bees, which make their 

 cells from pieces of leaf, Carpenter- Bees (Xylocopa), which cut out 

 cells one above another in the trunks of trees, and Flower- Bees 

 (Anthophord), forms which look something like humble-bees. 



Fig. 227. Bees and Flowers of Broad-Bean 



i, Wood-Bee (B. leucorum}. 2, 2, Holes cut by bee in bases 

 of flowers. 4, Humble -Bee (Bombus terrestris) extracting 

 nectar through one of the holes. 



Order 7. NET-WINGED INSECTS (Neuroptera) (fig. 228) 



This order, which is much smaller than some of those already 

 dealt with, contains a great variety of forms which differ very 

 widely in appearance. The most typical members of the order 

 possess four membranous wings exhibiting an elaborate net-work 

 of nervures, quite unlike the simple arrangement characteristic 

 of Hymenoptera. The mouth-parts are usually adapted for biting. 

 Eleven families are recognized, arranged in five groups; i.e. 

 i. Dragon -Flies, May -Flies, and Stone -Flies; 2. Flat -winged 

 Neuroptera; 3. Caddis -Flies; 4. White Ants and Book -Lice; 

 5. Biting- Lice. 



i. Dragon- Flies, May -Flies, and Stone-Flies all possess the four 

 typical wings and pass through an aquatic larval stage. Dragon- 

 Flies are among the most beautiful objects to be seen in the course 

 of a summer walk in the country. The four large wings are of 



