414 



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



i\ i '% w Mr 1 



Ml 



F' 



Fig. 3 



F f F' f FfF'fFfF'fF f 



— Chitinous lining of the gizzard of Argia agrioides Calvert, female, from 



Baja California. 

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



In Argia agrioides the arrangement is similar, but the 

 eight large folds themselves show an alternation, four of them 

 (E) being .26— .3 mm. long and bearing twelve to twenty- 

 four curved, sharp-pointed teeth .02-. 03 mm. long, while 

 .1 mm. behind the posterior end of each of these four folds 

 is a patch : .05 mm. long of ten to twelve small teeth .005 

 mm. long, which are directed anteriorly . The other four 

 (■F*') of the eight large folds are .15-. 2 mm. long, and bear 

 ten to seventeen teeth, of the same shape and size as on the 

 preceding four folds; these teeth are consequently closer 

 together, but there are no patches of small teeth following. 

 The eight small folds {/) bear from one to nine teeth like 

 those of the eight large folds. 



FrG. 4.— Chitinous lining of the gizzard of Erytliragrion sahmm Hagen, male, from 

 Baja California. 

 (Camera lucida drawing. Reichert oc. 4, T.eitz obj. 3, draw-tube out). 



In Erythragrion salvum there are eight larger folds, .13 

 mm. long, bearing six to nine straight, sharp teeth .007-. 026 

 mm. long, so arranged that on each fold they increase in 



1 Only three of these patches which follow folds ( F) are shown in fig. 3; the fourth, 

 or that nearest the left hand, was accidentally omitted by the engrax-er. 



