112 Miscellaneous. 
The Cockroaches of the Carboniferous Epoch. 
By M. Cuarztes Bronenrart. 
In the neuration of the first pair of wings Mr. Scudder finds little 
difference between the recent and fossil cockroaches. The latter he 
divides into two families, the Blattinarie and the Mylacride, dis- 
tinguished chiefly by the arrangement of the mediastinal nervyure. 
In the Blattinariz the branches of this nervyure start at regular 
intervals from a common trunk, so that the mediastinal area is 
usually in the form of a band. In the Mylacridz the branches of 
the mediastinal nervure originate from a common point at the base 
of the wing and appear to be arranged in a radiate manner around 
this point. 
Hitherto the Mylacride have been regarded as peculiar to the 
United States, but the author states that they are as numerous as 
the Blattinariz: at Commentry, where more than six hundred impres- 
sions of them have been collected by M. Fayol. 
As authors have generally had only wings at their disposal they 
have been unable to give any precise information as to the form of 
the body. M. Brongniart now confirms Mr. Scudder’s division of the 
group into Blattinarie and Mylacride by characters drawn from the 
body. ‘The Blattinariz have a very rounded prothorax, narrower 
than the part of the body covered by the wings; the Mylacride 
have a thickset body with a wider prothorax, which, instead of 
being rounded, is nearly in the form of a triangle with the base in 
front. 
But these two families have a common character which distin- 
guishes them from the recent Blattariz. The last dorsal arch of 
the abdomen in the fossils is widened, rounded, and divided into 
three parts by two longitudinal grooves. In the males the last 
ventral arch presents nothing extraordinary—it is truncated; but 
the females, instead of presenting, like the existing species, a keel- 
like last ventral arch cleft longitudinally in the median line to facili- 
tate the deposition of the ootheca, have this arch terminated by a 
sort of slender borer, as long as the abdomen, widened a little and 
keel-shaped at the base, but straight towards the extremity. This 
apparatus resembles the ovipositor of Hurycantha among the 
Phasmide rather than that of the Locustide. 
The presence of this borer leads to the supposition that the Car- 
boniferous Cockroaches, instead of leaving their eggs on the ground 
enclosed in an ovigerous capsule, probably deposited them singly, 
like the existing Phasmide, perhaps introducing them, by means of 
the borer, into the trunks of trees.—Comptes Lendus, February 4, 
1889, p. 252. 
