Charles Brongniart — Fossil Insects of the Primary Rocks. 485 



2. Platephemera antiqiia. — It is with reason that Scudder placed 

 this wing in the family of the Epheme ridge; Hagen is mistaken in 

 wishing to refer it to the Odonata. This wing reminds one much 

 of that of Palingenia virgo ; but the fossil is seven times larger than 

 the latter. 



3. Lithentomum Hartii. — The remains of a wing thus named by 

 Soudder are considered by that author as belonging to a neuropterous 

 insect of the group of the Sialina. He creates for it the family of 

 the Cronicosialina. So much trouble appears to me useless, the 

 specimen not being, in my opinion, sufficiently well preserved, to 

 permit the appraising of the characters of this fossil. 



4. Homothetus fossilis. — The wing that Scudder describes under 

 this name presents characters common to the Neuroptera and the 

 Orthoptera. He creates the family of the Homothetid^ for it. 



I have been able to compare the figure given by Scudder with 

 some insects from Coramentry, and am convinced that this type is 

 near to the Ephemeridas (genera Ephemera and Potamantlius). 



5. Dyscritus vetnstus. — In spite of the smallness of the fragment 

 represented, it ought, in my opinion, to be classed in the same family 

 (Ephemeridse or Homothetidae). 



G. Xenoneiira antiquorum. — The imprint which the author describes 

 is curious, because it presents at the base of the wing some striae, 

 which have induced a belief in an apparatus of stridulation. 



Scudder, having regard to the absence of reticulation between the 

 widely separated nervures, thinks that this insect forms a special and 

 extinct family in the order of the Neuroptera. I am much of his 

 opinion with respect to all these Devonian insect remains ; but I 

 believe that in the present state of our knowledge it is impossible 

 to be quite certain; we must wait further discoveries. Nevertheless, 

 if Mr. Scudder's opinions are to be accepted, one must believe 

 that the Neuroptera, the Neurorthoptera, and Orthoptera pseudo- 

 Neuroptera were already in existence during the Devonian epoch. 



Carboniferous System. — It is in this system that we begin to 

 find a pretty large variety of insects, and, thanks to the grand dis- 

 coveries made at Commentry, we are able to establish a little order 

 in this very interesting subject of the Paleozoic Hexapoda. 



The number of works published on these insects is already con- 

 siderable, and we owe much to MM. Germar, Goldenberg, Geinitz, 

 Sterzel, Van Beneden, Dana, Lacoe, Woodward, Andree, Goss, and, 

 above all, to Scudder, for having studied with patience and persever- 

 ance the materials that they have had in their hands. 



But as the number of the fossil remains that they have made 

 known was relatively small, it has been very difficult for them to 

 give a comprehensive view of the entomological fauna of these ancient 

 times. 



This task has been for me an easier one, seeing that I have had at 

 my disposal a series of well-preserved and numerous specimens. 



lam therefore about to sketch out a Pkodromus of the Hexapoda 

 OF TnE Coal epoch. 



1. Orthoptera. — Glaus places the Thysanura among the Ortho- 



