40 the canadian entomologist 



Key to the Families of the Order Perlaria. 

 'Anal fan of hindwing well formed, and with a complete archedictyon or 

 original meshwork of cross-veins; the contour of the outer margin of the 

 hindwing a single convex whole, without any re-entrant angle at the end of 



Cu2 Eustheniidce, n. fam. (Text Fig. 1). 



Anal fan of the hindwing without any archedictyon ; outer margin of hind- 

 .wing with a marked re-entrant angle at end of Cu2 2. 



(1) 



/"Anterior coxae closely approximated; cross-venation retained except on 



(2), anal fan; mandibles reduced to a weak lamina PteronarcidcB. 



lAnterior coxa; remain widely separated 3. 



'Mandibles reduced to a weak lamina; clypeus and labrum become hidden 

 (3) j beneath frontal shelf; last joint of tarsi much longer than 1 + 2...PerlidcB. 

 Mandibles, clypeus and labrum remain normal; last joint of tarsi not longer 

 [than 1 -f 2 4. 



(4)-, 



(5) 



(6) 



In forewing, three anal veins are present, lA running very close 



to Cu2 AustroperlidcB, n. fam. (Text Fig. 3). 



In forewing, lA is eliminated, leaving only 2 A and 3 A, the latter forked or 

 ^simple 5. 



In both wings, no true anastomosis connects the main veins from R to 

 Cui near middle of wing; cross-veins are always present in the distal portion 



of the wings Leptoperlidcs, n. fam. (Text Fig. 4), 



A true anastomosis or transverse cord is always present, connecting the 

 main veins of both wings from R to Cui; cross-veins not usually present 

 distad from the anastomosis 6. 



'(In forewing, 3A is forked; cerci are vestigial, being reduced to a single 



j oint Nemon ridce. 



In forewing, 3A is simple; cerci remain long and many- 

 jointed CapniidcB 



Family Austroperlid^. 

 Tasmanoperla, n. g. 



(Text Fig. 3). 



Allied to Aiistroperla Needham. from which it differs only in the following 

 points : — 



\^eins of the forewing very strongly marked, cross-venation very prominent, 

 [Aiistroperla has the cross-venation weak, especially in the distal half of the 

 wing, where the cross-veins are not easy to see in most specimens). In the 

 forewing, lA diverges from Cuo slightly, then converges towards it distally; (in 

 Aiistroperla \h\ie.swevy close to Cu2 throughout, and is a much more weakly 

 formed vein). Forewing considerably narrowed at the base, without any 

 clearly marked anal angle; (in Aiistroperla, the forewing has a definite anal 

 angle, distad from which the posterior margin runs almost parallel with the 

 costal margin of the wing). 



Genotype. — Eiisthenia diver si pes, n. sp. (Tasmania). 



