May, '07] 



ENTOMOLOGICAL NEWS. 



20I 



The Differentials of Three North American Species 



of Libellula. 



By Philip P. Calvert. 



In the News for January, 1907, p. 30, was mentioned that, 

 during our recent trip to Mexico, Libellula flavida (Hagen, 

 not Ramb.), new to that country, was taken. This capture 

 has led me to study this species, in order to include it in the 

 Supplement to the Odonate part of the Biologia Centrali- 

 Americana. 



In a footnote to page 73 of Prof. J. B. Smith's List of the 

 Insects of New Jersey (27th Annual Report, New Jersey State 

 Board of Agriculture, Supplement, 1900), I stated, "I have 

 examined Rambur's presumed type of flavida at Oxford, Eng- 

 land. It is identical with plumbea Uhler, and therefore differ- 

 ent from flavida Hagen, which latter will require a new 

 name." For flavida Hagen (nee Rambur), I now propose 

 Libellula comanche. 



The nearest allies of Libellula comanche are L. flavida Ramb. 

 and L. cyanea Fabr. These three species agree in having the dis- 

 coidal triangle of the hind wings cross-veined, supratriangular 

 cross- veins usually present on the front wings, usually absent 

 on the hind, one cubito-anal (submedian Selys*) cross-vein, a 

 bicolored pterostigma, and abdominal segment 8 of the female 

 perfoliate. 



The differentials of these three species follow. Having be- 

 fore me 7 <? , 4 $ each of comanche and of flavida, I have used 

 the same number of cyanea for this comparison ; all the avail- 

 able males of comanche are pruinose. 



Character. 



Vertex at apex. 



Frons 



$ 



L. comanche, nom. 



nov. 

 (flavida Hagen.) 

 With a yellow or 



orange spot. 

 Cream-yellow. 



Cream-yellow to 

 orange. 



L. flavida. 



{plumbea Uhler). 

 Without such a 



spot. 

 Bluish-black. 



Reddish-yellow to 

 greenish-brown. 



L. cyanea. 



(quadrupla Say.) 

 Without such a 



spot. 

 Greenish-brown 

 (young) to bluish- 

 black. 

 Greenish-yellow to 

 olive. 



* The Comstock-Needham wing-vein nomenclature is here employed, the Selysian synonyms 

 being added in parentheses. 



