ORTHOPTERA. 561 



There are about 5,000 species known, which attain their 

 greatest development in size and numbers in tropical countries. 



In studying these insects, the proportions of the head, of 

 the prothorax, of the wings, of the hind legs, and the external 

 genital parts, should especially be taken into account. The 

 ornamentation varies greatly even in the same species, and 

 therefore large numbers of individuals are necessar}'^ to ensure 

 a proper knowledge of any species. 



The different sounds produced by Orthoptera should be care- 

 fully studied ; every species can be distinguished by its pecu^ 

 liar note, and as in different families the musical apparatus 

 varies, so each family has a characteristic chirrup, or shrilling, 

 consisting of a harsh, grating, rasping noise. 



Mr. Scudder has contributed to the ''American Naturalist," 

 ii, p. 113, an interesting article on the sounds produced by 

 some of our native species of Grasshoppers, and has even 

 reduced their notes to a written music. He states that grass- 

 hoppers stridulate in four different ways: "first, by rubbing 

 the base of one wing-cover upon the other, using, for that pur- 

 pose, the veins running through the middle portion of the 

 wing ; second, by a similar method, but using the veins of the. 

 inner part of the wing ; third, by rubbing the inner surface of 

 the hind legs against the outer surface of the wing-covers ; and 

 fourth, by rubbing together the upper surface of the front edge 

 of the wings and the under surface of the wing-covers. The 

 insects which employ the fourth method stridulate during flight, 

 — the others while at rest. To the first group belong the 

 Crickets (Grjdlidse) ; to the second the Green or Long-horned 

 Grasshoppers (Locustariie) ; to the third and fourth, certain 

 kinds of Short-horned or Jumping Grasshoppers (Acrydii)." 



The transformations of grasshoppers need careful study. 

 For this purpose their eggs should be sought for, and the de- 

 velopment of the embryo in the egg be noted ; also the follow- 

 ing facts should be ascertained : the date of deposition of the 

 eggs ; the manner of laying them ; how long before the embryo 

 is hatched ; the date of hatching ; how man}- days the pupa 

 lives ; so also of the pupa and of the imago, while the inter- 

 vening changes should be carefully observed. Crows and 

 blackbirds feed on their eggs and larvas, and hens and turkeys 

 86 



