their subdivisions (pp. 22, 24). The line for the Homopters is made to run lowest on account of the Aphids and Coccids,

which seem to be inferior even to the Pediculi of the Hemipters and Nirmids of the Orthopters.

Designations of the successive grades of groups.

The parallelism between the grander subdivisions of the Pterometasthenics (Coleopters, Hemipters and Orthopters) and those of the Apipens, (Hymenopters, Dipters and Aphanipters,) and Amplipens, (Lepidopters, Homopters and Trichopters,) teaches that these subdivisions are coördinates, or of one grade. This is further indicated by other points of parallelism, namely, that the first subdivision of the Pterometasthenics and Apipens, the Hymenopters and Coleopters, have eminently the features each of a high type; and the last, the Aphanipters and typical Orthopters, are alike metapodosthenic or saltatorial species. So also under the Amplipens, the 2nd subdivision, or that of Homopters, is closely related to the second of Pterometasthenics, or that of Hemipters (page 27).

Hence, if the grander subdivisions of Apipens and of Amplipens are called tribes, those of the Pterometasthenics should also be so designated.

Under the subkingdom of Articulates, there are the classes of Insecteans, Crustaceans and Worms; and under Insecteans, the orders Insects, Spiders and Myriapods.

If then the term tribe be used for the familiar groups, Hymenopters, Dipters, &c., as just suggested, the question comes up as to the designations of the two intermediate grades of groups between orders and tribes.

The distinctions on which they are based are so obviously ordinal that they may be well called orders of subordinate grades; and I propose for the first of the two the designation suborders, and for the second ordinules, a diminutive of orders. The stages will then be as follows.

Orders: Insects, Spiders, and Myriapods.

Under Insects

Suborders: 1 Pteroprosthenics, 2 Pterometasthenics, 3 Thy

sanures.

Ordinules (confined to the Pteroprosthenics): 1 Apipens, 2 Amplipens, 3 Attenuates or Neuropters.

Pterometasthenics.

Coleopters.

1. Hymenopters. Lepidopters. Apipenniforms. Tribes, 2. Dipters. Homopters. Amplipeuniforms. Hemipters.

3. Aphanipters. Trichopters. Perattenuates.

Orthopters.

The subdivisions of the three tribes under the Attenuates or Neuropters, (p. 22,) and those of the tribes of Orthopters, (p. 24,) may be all designated subtribes; there is in the two higher of each a like reference to the higher tribes of Insects.

This subject will come up again for further discussion. But, for comparison, I allude here to one other department of animal life-that of Mammals.

The orders of the class of Mammals, as explained in former papers, are (1) Man, (2) Megasthenes, (3) Microsthenes, (4) Oötocoids; and in the distinctions between the highest of these orders, there is an example of the retroferent method, case a, as in the distinctions between the highest of the orders of Insecteans. Hence there is reason for concluding that the orders of Mammals and those so-called of Insecteans are actually all orders, or are groups of coördinate value. See further on this point, page 350, Art. I.

Under these orders of Mammals, (a class few in species), there are no suborders or ordinules; the next grade of groups is that of tribes, namely, as explained on page 341, of Art. I:—I. Under Megasthenes, (1) Quadrumanes, (2) Carnivores, (3) Herbivores, (4) Mutilates; II. Under Microsthenes, (1) Chiropters, (2) Insectivores, (3) Rodents, (4) Edentates. There appears to be no occasion for doubting that these subdivisions are coördinates with the tribes of Insects. As groups they stand out before the eye and mind of the zoologist with similar prominence and distinctiveness in their respective subkingdoms.

Geological History.-The memoir of A. S. Packard, Jr., which has afforded so many convenient illustrations of our subject, aims especially to show that Neuropters are remarkable among Insects for their many relations to the other tribes, or for the number of "synthetic" types which they embrace. The classification explained throws into their natural relations these affiliating groups, and shows that the many interlinkings are dependent on the position of this tribe as the lowest or hypotypic group of Pteroprosthenics, and its correspondence in grade with the Orthopters or the hypotypic group of Pterometasthenics.

But there is further reason for the many analogies, in that the Neuropters and Orthopters, while at the base of their respective

grand divisions, lead off apparently in geological time the Insects of the globe-the Neuropters the pteroprosthenic, and the Orthopters the ptcrometasthenic, Insects.

In view of this fact, we should naturally expect to find among the early representatives of these tribes foreshadowings of the higher tribes of Insects, that is, comprehensive (or synthetic) types embracing some of the characteristics of those higher tribes. Now two of the subdivisions of both Neuropters and Orthopters, in the classification proposed, consist mainly of such comprehensive types, and these were the forms which were apparently most characteristic of the Carboniferous Insect-fauna: namely, Termitideans or the Hymenopteroids and Planipennians or the Lepidopteroids, among Neuropters; and Cursors or the Coleopteroids and Ambulators, among Orthopters. With these there were also the typical Orthopters or Saltators, (Crickets being among Carboniferous species,) and possibly also Coleopters. Nothing is yet known of ancient Thysanures, although it is probable they were in existence at the same time.

We should expect also from the association of the Neuropters and Orthopters in the same Carboniferous fauna that there would be examples of intermediate types between these tribes, that is, those which, while related fundamentally to one of the two tribes, presents some characteristics of the other; for in this way the striking harmony in the flora or fauna of an age in geological history was often produced, as, for example, in the land-vegetation of the Carboniferous era, which embraced common Acrogens (Ferns) and Gymnosperms; and besides these, the intermediate or comprehensive types of the Lepidodendra and Calamites of the former, and that of the Sigillaria of the latter. And thus it was in fact. The Insect from the Carboniferous rocks of Illinois, figured and described in the following article, is one example of a comprehensive type of this kind. While Neuropterous in wings, closely approaching the Semblids, it has broad costate femurs, and even a large spinous joint to the anterior legs, peculiarities which seem to be almost inconsistent with the Neuropterous type, although in part characterizing the Mantispids, and which are in complete harmony with the Orthopterous type.'

We here see that the interlinkings between Orthopters and Neuropters began in the Paleozoic. It is probable that such comprehensive or intermediate forms were more numerous in the past than they now are.

• The Orthopterous features among Neuropters appear to be modifications of form under the types in this group which have been already mentioned, especially the Lepidopteroid, and not indications of a distinct type of Orthopteroid Neuropters. The fossil species referred to, and also the modern Mantispids, are true Planipennians in their wings and in their other characteristics of special importance. They properly constitute an Orthopteroid group in this subtribe.

AM. JOUR. SCI.-SECOND SERIES, VOL. XXXVII, No. 109.—JAN., 1864.

ART. IL-On Fossil Insects from the Carboniferous formation in Illinois; by JAMES D. DANA.

The remains of Insects, represented in the following figures, were discovered by Mr. John G. Bronson in the Carboniferous beds at Morris, Illinois.

They occur in the flattened iron-stone concretions of the beds. Other concretions of the locality contain various coal plants, and also the remains of two or three species of Amphipod Crustaceans. The plants have been investigated by Mr. Lesquereux and descriptions of them, we understand, will appear in the Report on the Geology of the State by Mr. Worthen. Among them, according to Mr. Lesquereux, the following are common species: Neuropteris hirsuta Brgt., N. rarinervis Brgt., Pecopteris Miltoni Brgt., P. unita Brgt., P. æqualis Brgt., Annularia longifolia Brgt. The description of the Crustaceans we reserve for another time.

Figure 1 is twice the natural size lineally. In general form and the neuration of the wings the Insect is close

ly like the Semblids among

the Neuropters, and especially, as I am informed by Dr. LeConte, the Chauliodes. In view of this resemblance, and also the fact that the outer wings are so thin as not to obscure at all the outlines of the abdominal segments, and hardly the inferior wings, there is no reason to doubt that the species was pteroprosthenic, and that therefore it must have been a Neuropter, and not an Orthopter. Yet in the broad costate femurs of the second pair of legs, and the form of the prothorax, it approaches the Orthopters of the Phyllium family, and is very unlike any known Neuropters. The anterior legs are peculiar in having a large and broad femur armed above with very slender spines as long as the joint, three

of which, though mutilated, are seen in the specimen. But something of this kind is observed under Neuropters in the Mantispids. It is quite probable that these anterior legs were prehensile, as in Mantispa: and the fact that the tibia and tarsus are not in sight in the specimen favors this conclusion. Only the left leg in the specimen has the large joint tolerably perfect; in the right, however, it is sufficiently distinct to show that it had the same large size and was also spiculigerous. The coxal joints of this leg, are faintly indicated between this large joint and the anterior part of the somewhat prolonged prothorax.

The number of abdominal segments is ten, or one more than the typical number in Insects-as is true also of many Neuropters, the Lepisma, and some species of other tribes. The neuration of the wings and the form and relative sizes of the segments of the abdomen are well shown in the figure, and particular description is therefore unnecessary. There appears to have been a pair of short obtuse appendages at the extremity of the abdo men, much as in Phyllium. The head is mostly obliterated.

The length of the specimen, from the anterior margin of the large joint of the anterior legs to the posterior margin of the wings, is 1 inch 10 lines; and the breadth, from the medial line of the abdomen to the left margin of the left wing, 5 lines.

By request of the discoverer, I name the new genus here indi. cated, Miamia, after the Miami University, his "alma mater." In view of the important results of his explorations, the species may be designated the Miamia Bronsoni.

2.

Figure 2 represents, natural size, a mutilated anterior wing of another Neuropter. The neuration approximates to that in the genus Hemerobius. The dotted line shows the probable length and outline of the wing-these organs in the Planipennians being 3 to 4 times as

long as their breadth. The areolets are obliterated towards the base of the wing.

There appears to be sufficient reason in the character of the neuration for the institution of a new genus, and I propose for it the name Hemeristia (from hueça day, one of the roots of Hemerobius), designating the species Hemeristia occidentalis.

The feebleness of the life-system in most Neuropters is shown. in the numerous nervures of the wings; and this is very marked in this ancient species. The great multiplication of these nervures and their irregularity appears to be owing to a want of directive force in the system, or to a low grade of cephalization or systemic control in the animal.