confluens Say.

falconis Har.

MELOPHAGUS?
ovinus Linn.

My scientific knowledge of the Diptera of Lancaster county is very limited, and therefore the foregoing catalogue of these insects is nothing more than an imperfect compilation from the works of Say, Harris and Fitch-with Harris' classification-as an approximation to what may be presumed to be the dipterous fauna of the county, from its geographical position, and its relation to other portions of the northern and middle States of the Union. S. S. R.

ORDER APHANIPTERA.

This is the order APTERA of Macley, and includes the wingless insects; an example of which is the common "Flea"-Pulex irritans. Not all insects however, that are destitute of wings, are members of this order; for there are various species, the females of which are wingless, and in some instances both sexes, in other orders. As instances of this kind, it may be remarked, that several species of predaceous Coleoptera are wings less, although they have wing-covers. There are also wingless species both male and female among the Orthoptera; and females among the Hemiptera; and among the Hymenoptera, and Lepidoptera, as well as the Diptera. This subject constitutes one of those anomalies in natural history, which can only be solved by the patient and persevering progress of the entomological student. The order Aphaniptera might perhaps be properly restricted to a single small family. PULECIDE, which includes the various species of fleas, that infest men and animals. The PODURIDE, which by some entomologists are regarded as degraded species of Neuroptera, may, for the present with some propriety, beplaced in this order. These insects undergo the usual transformations, from the egg to the imago, that all other insects do, but they lack the distinctive divisions of head, thorax and abdomen, that characterizes the other orders, being merely a series of segmental rings, from the head to the caudal termination of the abdomen. In their larva state they are long, distorted, wormlike grubs, which however spin themselves into a sort of silken coccoon, and assume the pupa form, in which the legs, antennæ, and sucking apparatus are visible. Emerging from this state, they assume the mature form, in which the Pulecido have the hind feet developed into leaping appendages, and the external integument tough and shiny, each segment being fringed with a few stiff bristles. In this form they attack men and animals, living upon the blood they extract from them by means of their powerful piercers.

The Podurida, as before stated, are regarded by many naturalists as merely degraded forms of Neuroptera, allying them with the genera Ephemera and Perla, and therefore perhaps they cannot properly be classed with the Order APTERA, scientifically restricted.

CLASS MYRIA PODA.

rous.

As the name implies, this class is composed of oblong or long animals, with many feet, of which there are not a large number of species found within the limits of Lancaster county; and although some of them are very common, yet very little attention has been devoted to their specific history by a resident naturalist. Of this class there are two divisions, very distinct in their structure, form and habits-commonly called Centipedes and Millipedes. “The Myriapoda are air-breathing apterous articulata, characterized by the distinctness of the head from the body; the strongly marked segmentation of the latter, and its method of development." According to specialists, they constitute two distinct Orders. called CHILOPODA, including the centipedes; and DIPLOPODA, including the millipedes. The former are known, in many instances, to be carnivorous in their habits, and some of the latter are equally well known to be herbivoThe Chilopods comprise those that have the body flattened with a limited number of segmental rings, to each of which is attached a single pair of feet, at the sides. The diplopods on the other hand have the body tube-shaped, or cylindrical, with a double pair of feet attached to each segment, beneath. The former are very swift runners, whilst the latter seem to glide along very slowly, and when interrupted throw themselves over on the side in a spiral coil. There is, however, a subdivision of the Chilopoda called CHILOGNATHA, which seems to be a connecting link between the two orders above named. These possess the flattened bodies, with the legs articulated at the sides; but there are two pairs to each segment, and like the diplopoda, they are slow travellers. Large species of the diplopods-from three to four inches in length-are found in the wooded valleys of Lancaster county, especially in the southern tier of townships. These have been detected feeding upon the various species of fungi that are common to those localities. Although the common names of Centipedes and Millipedes, applied to these animals, would seem to indicate that they possess respectively a hundred or a thousand feet; yet there are species that exceed the first number, but none that reach the last.