64 ^A' ECONOMIC ENTOMOLOGY. 



the thoracic parts large and not closely united, the wings exceed- 

 ing the abdomen in length. In texture they are rather soft, and 

 the antennae are long and many-jointed. They frequent the 

 margins of streams and running ditches, preferring damp, shady 

 localities. The mouth parts are mandibulate, but their food 

 habits are not well known. They are not injurious, and are 

 economically important only as food for fishes. The eggs are 

 laid in masses upon the surface of the water, through which they 

 sink to the bottom. The larvae are flattened, live among and 

 under stones, feeding upon vegetation, and probably also upon 

 such small, soft-bodied creatures as come in their way. The legs 

 are well developed and of nearly equal size. The antennae are 

 long and slender. There are usually slender, hairy appendages 

 at the end of the abdomen, and on the under side are tufts of gill- 

 like structures serving for respiration. In some species these 

 gills persist even in the adult, forming a remarkable exception to 

 the general rule that adult respiration is through spiracles only. 

 One natural family the Perlidce, comprises the entire order. 



Order PLATYPTERA. 



The ordinal term signifies " flat winged," or " broad winged," 

 and in those forms in which wings are present the secondaries 

 are not folded or plaited, but lie flat over the body, covered by 

 the primaries. The mouth parts are mandibulate, the thoracic 

 rings are loosely jointed, and as a rule the insects have a flattened 

 appearance. In most cases the head is large and prominent, 

 wider than the thoracic rings. 



Three distinct families, using that term loosely, are grouped in 

 this order, diflering greatly from each other, all of some economic 

 importance, and requiring more detailed consideration. 



Family termitid/E. 

 Termites, or "white ants," as they are called, from their 

 appearance and habits, occur all over the United States, but are 

 more common southward. They are separated as a distinct 

 order under the term Isoptera^ meaning similar-winged, and are 

 interesting from their social organization, which is complicated, 

 several forms or castes existing in each colony. All our species 

 live in and feed upon woody or fibrous material, though extend- 



