250 



PROCEEDINGS OF THE ACADEMY OF 



[May, 



Table I. 



Positions of Certain Wing-details in Decimal Parts of Wiyig-length for 

 Certain Odonata. 



The measurements have been made from a single wing only in each species 

 (front wing in living species). 



Genus and Species. 



(Recent, except where otherwise marked.) 





Protomyrmeleon brunonis (Lias) 



Tarsophlebia eximia (Jurassic) 



Euphseopsis multinervis (Jurassic) 



Steleopteron deichmiilleri (Jurassic) 



Dysagrion packardii (Eocene) 



Phenacolestes mirandus (Miocene) 



spmn. No. 3 



Phenacolestes mirandus (Miocene) 



spmn. Xo. 5 



Thaumatoneura inopinata cf 



" pellucida c? 



Melanagrion umbratum (Miocene) 



Rhipidolestes aculeata c? 



Argiolestes icteromelas cf 



9 



Allopodagrion nebulosum cf 



Lithagrion hyalinum (Miocene) 



Philogenia carriUica cf 



9 



" terraba cf 



Paraphlebia zoe cf 



" 9 



" abrogata cf 



Dimeragrion percubitale cf 



Heteragrion tricellulare cf 



Perilestes fragilis? cf 



Summary : 



Maximum 



Minimum 



Range 



.2§[.2§ 



.15, 



.45 .87 



.44 



.30 



.39 .87 



.83 



.33 



.34 

 .18 

 .18 



.29 .83 



,29 .93 

 .30 



.28! -89 



.29 .90 



.34 .88 



.23 .91 



.24 .90 



.25! .91 



.19 .93 



.19 .95 



.20 .92 



.25 .81 



.23 .91 



.28 .88 



<^ 



^--^''=*-,' 



'■^ 





g S 



.48; .21 (None)! 71.53 



.47 .38! .14 .33 .15 



.52 



CO o* 



5 : 



o S 



c a 



,2:s 

 Is 



^ 2 



13 .29 .18 



.14; .26 



.08 .17 



.08! .16 



.16 .25 



.18 .25 



.171 -28 



.16 .28 



.181 .27; 



.20: .28! 



.16 .23 



.16 .24 



.16 .23 



.12 .20 



.13 .20 



.14 .22 



.16 .25 



.16 .25 



.21 .36 



.49 .21 .36 

 .19 .08 .15 

 .30 .13 .21 



.02 



.08 .15 .13 

 .lO! .23 .15 .16 

 .15 .30 .17 .07 



.10 



.11 

 .06 

 .06 

 .15 

 .20 

 .18 

 .18 

 .16 



.20 

 .12 

 .12 

 .27 

 .22 

 .22 

 .21 

 .21 

 .24 .23 

 .20 .18 

 .21 .20 

 .20 .19 

 .19 .17 

 .19 .18 

 .22, .21 

 .19 .18 

 .20 .15 

 .25 ^2 



™ The number in parenthesis at the top of each vertical column is that under 

 which that character has been treated throughout this paper, 

 ^1 In Protomyrmeleon brunonis Ms separates from Rs. 

 " A not developed as a vein separate from the hind margin. 



