XVII. A Review of Mesozoic Cockroaches. 

 By Samuel IT. Scudder. 



Read January 20, I88G. 



OIX years ago, when I published a revision of all the paleozoic cockroaches then known, 

 I was obliged to resort entirely to existing forms in the comparisons instituted between 

 the wing structure of the ancient types and that of those of later times. Illustrations 

 "indeed and partial descriptions existed of more than thirty mesozoic forms, but since many 

 of these were very imperfect, and many vaguely drawn, any attempt to reach definite 

 conclusions concerning them, without specimens themselves from that period to examine, 

 seemed futile. 



It Avas my hope that, since structural distinctions of fundamental importance and 

 of complete uniformity were shown to exist between paleozoic and recent cockroaches, 

 rendering an examination of the mesozoic forms most desirable, some English nat- 

 uralist would undertake the task; for it was evident, from the illustrations already 

 given by Brodie and Westwood, that the British Lias and Oolite were especially prolific 

 in these forms, and that abundant material must exist in public and private collections 

 for the elucidation of the problems suggested. 



This hope has not been fulfilled; but an unexpected discovery of Triassic cockroaches 

 in considerable abundance in the South Park of Colorado rendered the examination of 

 other mesozoic forms still more desirable, and I determined, therefore, to study the ques- 

 tion myself as best I could. My venerable friend, the Reverend P. B. Brodie, the pioneer 

 student of British fossil insects, kindly came to my aid by sending me, from his unex- 

 ampled collection of British mesozoic insects, such specimens as seemed to be cockroach 

 wings. In this way, I have not only been able to study from the specimens themselves 

 as many as ten of the wings which had before been described and figured, but nearly 

 three times as many forms now published for the first time. The study of these natu- 

 rally threw much light upon obscure points in the illustrations of species not studied 

 from the specimens, both in England and on the continent, — a number less than those 

 seen, and most of them easily interpreted with their aid and often without it. The fruits 

 of that study are herewith presented, with my best thanks to the Rev. Mr. Brodie for his 

 generosity. The number of mesozoic types now slightly exceeds the paleozoic, though 

 their relative proportion to the rest of the synchronous insect fauna is far less than in the 

 earlier period. 



MEMOIRS BOSTON SOC. NAP. HIST. vol.. III. 1 139 



