NEUROPTERA ODONATA. 125 



most nlmmlant, the Aeschnida- being represented by a species of Aesehna 

 at Schambeleii and the Goinphida 1 bv one species each of Petalura 

 and (iomphoides from England. Calopterygidse come next, with one 

 species each of Tarsophlebia and Heteropblebia, both extinct genera, also 

 fnun England, and finally a species of Libellula from England. The same 

 relation holds in passing upward into the ooliti.', where the Agrionina arc 

 added. Hen- we have thirty-two species, of which half are Agrionina: four 

 Agrionida 1 , and twelve < 'alopterygida' of live genera, mostly extinct, namely, 

 Isophlehia, two; 1 leterophlebia, two; Stenophlebia, three; Tarsophlehia, 

 one, and Eupha-a, four; three are Aeschnida' of the genera Anax and 

 Aeschna ; eight <!omphid;e of some undetermined genera, besides Petalura 

 and IVtalia ; and linallv live Lihellulida- of about as many genera, yet 

 undeseribed. A species of Gomphida' has also been found in the Wealden 

 of England. The lithographic slates of Bavaria afford numerous, some- 

 times wonderfully preserved, dragon-Hies, called l>v the workmen Stangen- 

 reiter or Schladen-Vogel, which have been carefully studied by Ilagen. 

 They lie on the stone with expanded wings ;md are generally larger than 

 modern types; sometimes the most delicate veins are perfectly preserved. 

 Most of them are referred to extinct genera. 



Considering the comparative Abundance of this group in the Second- 

 ary rocks one would expect to find a better representation in the Terti- 

 aries than is the case, for, even counting all the species founded upon the 

 immature Mai;v> as distinct from any of those established upon wings, the 

 Tertiary species are less than twice as numerous as those from the Second- 

 ary rocks. The subfamilies are about equally represented, though the 

 Agrionina are a little in excess, and the species are very unequally distrib- 

 uted among the tribes. Thus there are twenty-two species of Agrionidae of 

 the following genera : Agrion, seven ; Lestes, five ; Argya, one ; I'latycne- 

 mis, two; Sterope, one ; 1 )\sagrion, three ; Podagrion, one ; and Lithagrion, 

 tuo, the, last four genera being extinct; while there is but a single species 

 of Caloprerygida- known by a pupal form, from amber, a curious reversal 

 of the .proportion in Meso/.oic rocks. The .Eschnina are more equally 

 balanced between the tribes, the Gomphida- being represented by six 

 species, of the genera Gomplms, Gomphoides, Ictinus, and Petalura, and 

 the Aeschnida} by nine; of the genera Aeschna (eight) and Anax (one). 

 The Libellulina, however, have again only a single species of Cordulidse, 



