INTERRELATIONS OF PLANTS AND ANIMALS 31 



Another group of insects sometimes found on flowers in the fall 

 are flies. They belong to the order Diptera (two wings). These 

 insects are usually rather small and have a single pair of gauzy 



Forms of life to be met on a field trip. A, The red-legged locust, one of the 

 Orthoptera; o, the egg-layer, about natural size. B, the honey bee, one of 

 the Hymenoptera, about natural size. C, a bug, one of the Hemiptera, about 

 natural size. D, a butterfly, an example of the Lepidoptera, slightly reduced. 

 E, a hous3 fly, an example of the Diptera, about twice natural size. F, an 

 orb-weaving spider, about half natural size. (This is not an insect, note the 

 number of legs.) Or, a beetle, slightly reduced, one of the Coleoptera, 



