INTRODUCTION. 



tion in the thoracic segments and alar venation. This primary 

 division seems to be the least objectionable yet proposed, and 

 exliibits the most important affinities very clearly. 



In geological succession, the Neuroptera and Orthoptera ex- 

 tend far back into palteozoic time, and are, moreover, connected 

 together l)y some synthetic Ephemera and Perla-like forms of 

 large size; PahTeozoic cockroaches are also numerous. One palae- 

 ozoic Coieoptcron, said to be Scarabseide in its affinities has been 

 recorded: the presence of such a form in that remote age would 

 be quite impossible, and if Coleopterous at all, it must be a 

 Ilhynchophore. Some subcortical borings iu paUeozoic conifers* 

 would indicate the presence of a Scolytide. In the middle of the 

 mesozoic period Coleoptera were numerous, and not remarkable 

 ill any way, except as showing the more northern extension of 

 subtropical forms. 



The genus Eugereon,"|" found in Birkenfeld, Germany, in strata 

 of Permian age, indicates an order curiously synthetic between 

 Hemiptera and Neuroptera, which with some still older synthetic 

 types are classed together as Paloeodictyoptera. 



Fulgorina or allied forms occur in })al£eozoic strata. 



One Heteropteron (Phthanocoris) has been found in carbo- 

 niferous near Kansas City, Missouri. | 



The other orders, so far as known, appear in the mesozoic, and 

 successively increase in nuinl)er and variety up to the tertiary 

 period. In that period the entomological fauna seems to have 

 been very similar to that prevailing at the present time, and the 

 remains of Coleoptera and of other firmly chitinized forms are 

 found in certain localities in great abundance. 



In the scheme of orders given in the foregoing table several 

 so-called orders are attached as families to the principal types of 

 which they are extreme modifications. Thus Aphaniptera are 

 suppressed into Diptera; Achreioptera become the Coleopterous 

 family Platypsyllidse, and Strepsiptera become Stylopidse. The 

 Euplexoptera and Thysanoptera are united with Orthoptera, and 

 the Trichoptera become a sub-order of Neuroptera. A still farther 

 reduction has been proposed by Burmeister in suppressing the 



* Brongniart, Ann. Ent. Soc. Fr., 1877, 215, pi. vii. 

 t Dohrn, Stettin Ent. Zeitung., 1867, 145, pi. i. 

 t Scudder, Proc. Boston Soc. Nat. Hist., 1882, 59. 



