ORTHOPTERA 253 



hoppers. These are common and well-loiown insects. They differ 

 from most of the members of the two preceding famiHes in having 

 the antennee much shorter than the body, and consisting of not more 

 than twenty-five segments. The ovipositor of the female is snort 

 and composed of separate plates; and the basal segment of the 

 abdomen is furnished on each side with a tympanum, the external 

 parts of the organs of hearing (Fig. 277, t). 



It is to these insects that the term locust is properly applied; 

 for the locusts of which we read in the Bible, and in other books 

 published in the older countries, are members of this family. 

 Unfortunately, in the United States the term locust has been applied 

 to the Periodical Cicada, a member of the order Homoptera, described 

 later. And, what is more unfortunate, the scientific name Locus- 

 tidse has been applied by many writers to the long-homed 

 grasshoppers. 



Locusts lay their eggs in oval masses and cover them with a 

 tough substance. Some species lay their eggs in the ground. The 

 female makes a hole in the ground with her ovipositor, which is a 

 good digging tool. Some species even make holes in fence-rails, logs, 

 and stumps; then, after the eggs are laid the hole is covered up with 

 a plug of gummy material. There is but one generation a year, and 

 in most cases the winter is passed in the egg-state. This family is 

 of great economic importance, as the members of it usually appear in 

 great numbers in nearly every region where plants grow, and often 

 do much damage. 



With many species of the Locustidae the males are furnished with 

 stridulating organs. These have been described in Chapter II, 

 page 82. 



There are very many species of locusts in the United States and 

 Canada; these represent four of the subfamilies of the family Locus- 

 tidae, which can be separated by the following table. 



A. Claws of the tarsi with a small pad (arolium) between them; pronotum ex- 

 tending at most over the extreme base of the abdomen. 

 B . Prosternum armed anteriorly with a distinct conical or cylindrical tubercle. 



p. 254 LoCUSTINiE. 



BB. Prosternum without a distinct tubercle; arolium usually small or rather 

 small. 

 C. Head rounded at the union of the vertex and front ; front perpendicular 



or nearly so. p. 257 CEdipodin^. 



CC. Vertex and front of head meeting at an acute angle; vertex extending 



horizontally; front strongly receding, p. 259 Truxalin^. 



AA. Claws of tarsi without an arolium between them; pronotum extending over 

 the abdomen, p. 259 Acrydiin^. 



diidse, based on the generic name Acrydium of Fabricius; and still others use the 

 family name Acridiidae, based on Acridium, an emended spelling of Acrydium. 

 The oldest name given to this family is Acrydiana, applied to it by Latreille in 

 1802; but the group of insects that Latreille used as the type of the family is the 

 Locusta of Linnaeus (1758); for this reason the name given to the family by 

 Latreille has been changed to Locustidae. See also the footnote on page 234. 



