410 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3 d Ser. 



Structurally, Batesii is intermediate between furcata and 

 gravida, as the apex of the superior appendages of the male 

 is neither so tapering as in the former nor so rounded as in 

 the latter, while the anterior lamina is more prominent than 

 in furcata., less prominent than in gravida. An examina- 

 tion of specimens in the British Museum marked Cannacria 

 Smithii Kirby ] failed to show any specific differences from 

 furcata. 



III. Notes on Some of the Internal Organs. 



I have dissected a number of individuals of various spe- 

 cies both from Baja California and from Tepic. Attention 

 was chiefly paid to the thoracic and abdominal ganglia and 

 to the gizzard. 



The -prothoracic pair of ganglia is always distinct from 

 the mesothoracic, but the interval between this latter and 

 the metathoracic pair varies, although it is rarely as great as 

 that between pro- and mesothoracic or as long as are either 

 the meso- or metathoracic ganglia themselves; such an infre- 

 quent case is that of Hetarina americana. In Lestes tenuatus, 

 Archilestes grandis, Mecistogaster ornatus, Argia agrioides, 

 Erythragrion salvum, Her-petogomphus elaps, Diplax cor- 

 rupta and Dythemis sterilis, more or less of an interval was 

 apparent separating the mesothoracic from the metathoracic 

 pair. In Orthemis ferruginea and Mesothemis simplicicollis 

 var. collocata there was no such appreciable interval. These 

 results are not important, however, as it is very difficult to 

 define exactly just how great the interval may be, or to 

 avoid all tension on the parts in dissection. 



More important is the variation in the position of the first 

 pair of abdominal ganglia. The usual statement has been 

 that it is located in the first abdominal segment of all Odo- 

 nata. In Hetarina americana, Lestes tenuatus, Archilestes 

 grandis, Mecistogaster ornatus, Argia agrioides, Erythrag- 

 rion salvum, Ischnura Ramburii var. credula, all Zygop- 

 tera, the first abdominal pair of ganglia lie in the hind part 



1 Ann. Mag. Nat. Hist., 6th Ser., Vol. XIV, 1894, p. 266. 



