492 CALIFORNIA ACADEMY OF SCIENCES. 



upper and outer sides longer than the other two, outer 

 side more obhque than inner, color luteous. 



? Differs from $ as follows: a transverse, basal, black 

 stripe on labrum, 8-9 black in the Californian female, similar 

 to those of the Washington male in the Washington female ; 

 hind margin of prothorax distinctly bilobed; a very dis- 

 tinct, transverse, erect, triangular lamella behind each 

 mesostigma; no apical ventral spine or acute point to 8; 

 appendages black, three-fourths as long as 10 ; front wings 

 with 12-13 postcubita^s, nodal sector arising at sixth 

 postcubital in front wings, at fifth in hind wings, in the 

 Californian female only; pterostigma luteous, of nearly 

 equal size on front and hind wings, some double cells 

 after it. 



Abdomen S 25, § 24-26. Hind wing S 18-18. 5, ? 19-21, 



To write of the female that it possesses no ventral spine 



to the eighth segment is almost equivalent to excluding 



this species from Ischnura, but it is here so referred, with 



much hesitation, for the following reasons: 



1. As showai by the descriptions and figs, i and 2 pi. 

 XV, the appendages of the males of crratica and exstriata 

 are very similar, hence if exstriata be an Ischnura it is 

 difficult to believe that erratica is not closely allied. 



2. ^rrri-Z/crt 6 possesses the Ischnurine characters of 

 pterostigma and bifid process on 10. 



3. If the reference oi exstriata io Ischnura be correct, 

 licrht is thrown on the absence in erratica^- of the ventral 

 spine to the eighth abdominal segment by the circumstance 

 that in extriata^ {q. v.) the same spine is very short. 



4. It seems improbable that what have been above 

 described as erratica male and female belong to different 

 species, for not only do their colors resemble each other, 

 but the pair from Washington were sent by the collector, 

 Mr. Kincaid, to the writer enclosed in the same envelope 

 as if taken while pairing. 



