LOCUST 423 



In the female the eighth segment resembles the other segments, 

 except that the sternum is nearly twice as long, and known as the 

 subgenital plate. The ninth, tenth, and eleventh segments are essen- 

 tially like those of the male, the terga of segments nine and ten 

 being partially fused, and tergum eleven forming the terminal 

 dorsal shield. The plates called cerci and podical plates are similar 

 to those in the male, except that the podical plates are much more 

 prominent. 



The ovipositor consists of three pairs of movable plates. The 

 dorsal pair lies just ventral to the eleventh tergum and each plate 

 is long, lance-shaped, and with a hard, pointed tip. The ventral pair 

 arises just dorsal to the eighth sternum and resembles the dorsal 

 pair. When these four pieces are brought together, their points are 

 in contact, forming a sharp organ by means of which the female 

 bores the holes in the ground in which to deposit her eggs. The third 

 set of plates- are known as the egg guides. These are much smaller 

 and are located median to the plates of the true ovipositor. 



There are ten pairs of spiracles, or openings in the respiratory- 

 system, on the body of the grasshopper. Two pairs of these liplike 

 structures are situated on each side of the thorax on the anterior 

 margin of the pleural plates. The mesothoracic spiracle is con- 

 cealed by the posterior edge of the pronotum. The metathoracic 

 spiracle is located just dorsal to the mesothoracic leg, near the 

 suture separating the two segments. There is another spiracle just 

 dorsal to the attachment of the metathoracic leg, but this belongs 

 to the first abdominal segment. From the second to the eighth 

 abdominal segments there is one pair of spiracles located on the 

 anterior margin of each segment near the union of the sternum and 

 tergum. The spiracles are one of the most useful sets of structures 

 for determining the segmentation of an adult insect body. This is 

 because there are never more than eight pairs of abdominal spiracles 

 present in any fully developed insect. Air passes through the 

 spiracles into the tracheae and is carried to the tissues of the body. 

 This unique system of breathing enables the insect to keep the body 

 tissues well aerated and the carbon dioxide eliminated from the 

 body. 



The circulatory system consists of a single dorsal tube, or heart, 

 which extends along the length of the median dorsal part of the 

 body. In the abdomen of the fully developed insect this vessel is 



