— 25 — 



this region, and the fact that some authors have considered 

 the first abdominal sternum as a part of the metathorax. 

 Eight abdominal segments can be readily distinguished in 

 the female ; and nine, in the male.* Caudad of the eighth 

 abdominal segment of the female and the ninth of the male 

 are a number of sclerites which are considered by some 

 writers to be merely appendages of the abdomen ; other 

 writers hold that certain of these sclerites represent sterna, 

 and certain others, terga. 



It is not within the scope of this work to enter into any 

 discussion of the matter. I shall describe the parts as if 

 there were eleven segments ; but wish the student to under- 

 stand that the so-called eleventh segment may be merely an 

 appendage of the tenth ; and that what is described here as 

 the ninth and tenth segments have not been considered as 

 such by certain very high authorities. 



First Abdominal Segment. — The dorsal and ventral 

 parts of the first abdominal segment are widely separated by 

 the caudal part of the cavities for the insertion of the third 

 pair of legs. 



The ventral part of this segment is dove-tailed into the 

 metasternum, and at first sight would be taken for a part of 

 the thorax. 



On each side in the dorso-lateral part of this segment, 

 there is a large opening which is closed by a very delicate 

 membrane ; these are the auditory organs ; the membrane is 

 the tympanum . 



Just cephalad of each auditory organ there is a small 

 opening ; these are the first pair of abdominal spiracles. 



Second to Eighth Abdominal Segments — Each of the 



*If a sufficiently large series of specimens of the red legged locusts be examined, 

 it will be seen that there are two kinds : one, in which the caudal part of the body 

 tape* s to the end, and bears four, pointed and curved, horny pieces ; and another, in 

 which the caudal part of the body increases in size caudad and is terminated by a 

 single, large, hood-shaped plate. The former is the female ; the latter, the male. 



