412 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



second; in Pantala hymencea, Pseudoleon superbus, Micra- 

 thyria Hageni and Dythemis sterilis in the third ; in Orthe- 

 mis ferruginea, Trithemis basifusca, Tramea onusta, and 

 Mesothemis simplicicollis var. collocata in the fourth. 



In the preparation of the chitinous linings of the gizzards 

 described below, care was taken to open them along the 

 mid-dorsal line, an essential precaution in the case of the 

 Anisoptera though not so necessary in the Zygoptera, where 

 the small calibre of the alimentary canal renders this quite 

 difficult. 



FiQ. 1.*— Chitinous lining of the gizzard of Hetterina americana Fabr., male, from 

 Tepic. 

 (Camera lucida drawing, Reichart oc. 4, I«eitz obj. 3, draw-tube out). 



* The following explanation applies to the four text figures. These figures show the 

 chitinous teeth with which the gizzards are armed, while the lines represent the folds 

 into which the chitin is thrown, following the foldings of the other coats of the foregut. 

 In their natural position the teeth, with one exception noted in the text for Argia agri- 

 oides, point backwards. 



Although my preparations of the gizzard of Hetarina 

 americana are not entirely satisfactory, I believe that they 

 are sufficiently so to justify the statement that the armature 

 of the chitinous coat here consists of a girdle of four folds, 

 each covered with a great number of very minute teeth 

 (.002 mm. long) for a length of about .52 mm. and a width 

 of .05 mm. There are no large teeth and no intermediate 

 tooth-bearing folds. 



The armature of the gizzard of Archilestes grandis agrees 

 with that described and figured by Dr. Ris 1 for Lestes virens 



1 1. c, p. 615. 



