206 ORTHOPTERA OF NOVA SCOTIA. PIERS. 



part. The sides of the first abdominal tergum in short- 

 horned locusts (Acrididce) bear the "auditory organs" 

 or ears. Along the sides of the abdomen are several "spira- 

 cles" or small external openings of the respiratory air-passages. 

 The terminal abdominal segments are modified in each 

 sex, as there are located the generative organs. The 

 last tergum of the Mafe locust is a triangular plate called 

 the "supra-anal plate", at the base of which are usualh'^ a 

 pair of minute processes called "furcula"; and to the second 

 last tergum are attached two appendages called "cerci" 

 which extend on either side of the supra-anal plate, and the 

 form of which is sometimes, particularly in the Melanopli, 

 an important character for the identification of species. The 

 under portion of the last abdominal segment of the male 

 is termed the "subgenital plate". The abdomen of the 

 female ends in two pairs of plates, the "valves of 

 the ovipositor"; and between them is the "ovipositor" 

 proper or organ for depositing eggs. 



In passing, it may be merely remarked that one of the 

 most frequent questions regarding locusts asked by many 

 people is, What is the so-called grasshopper "molasses" 

 which most species readily exude from the mouth when 

 handled? This brown-coloured fluid is secreted bj' salivary 

 glands situated near the mouth-opening. It is also probably 

 defensive in character. 



Stridulation. — The call-notes of many species of Orthop- 

 tera are the most common insect sounds of late summer 

 and autumn. Males alone possess musical organs which 

 they use to call the opposite sex. Such organs, when present 

 at all, are only in species which have wings, and wingless 

 species also lack auditory organs. These call-notes are 

 not vocal as many suppose; for owing to their peculiar mode 

 of breathing through body spiracles and tubes without 

 attached vibratory organs, insects have nothing which 

 corresponds to a mammal's voice. The sound is produced 



