Zool.— Vol. I.] 



CALVERT— ODON ATA. 



4 J 3 



— eight fields covered with minute teeth .005 mm. long, four 

 of which are wider than the other four and alternate with 

 them. The wider fields have a width of .13-. 15 mm. and 

 a length of .45 mm., the narrow fields are .08-. 1 mm. wide 

 and .4 mm. long. A wide field occasionally bears also a 

 single large tooth .03-. 04 mm. long. 



Lestes tenuatus appears to be similar to Lestes virens. 



The gizzard of Mecistogasler ornatus is lined with such 

 extremely small teeth that their examination is a matter of 

 some difficulty. I believe that I can distinguish sixteen 

 fields whose width is alternately greater and less, although 

 the difference between a wide and a narrow field is not as 

 great as in Archilestes, and which are separated from each 

 other by intervals narrower than the fields themselves. The 

 teeth are smaller than those of HetcBrina americana, and I 

 can find no larger teeth. 



F f F 



/ F f F J F 



f F 



Fig. 2. — Chitinous lining of the gizzard of Argia pulla Selys, male, from Tepic. 

 (Camera lucida drawing, Reichert oc. 2, Leitz obj. 7, draw-tube in). 



In Argia -pulla there are eight folds (-F) not very greatly 

 chitinized, .15-. 18 mm. long, each bearing from six to nine 

 strong, straight or slightly curved, sharp-pointed teeth .015- 

 .02 mm. long. With these eight folds there usually, but 

 not always, alternate shorter and narrower folds (f), which 

 bear from one to three teeth of the same shape and size. 



