The study of forest and shade tree insects is a line of entomological work demanding especial attention in the State of West Virginia. During the past two years I have carried out quite an elaborate line of investigations and experiments on this subject. The first object was to conduct investigations with reference to the forest conditions, the distribution of forest trees, and the relation of certain kinds of forest growth to the occurrence and range of the several life zones, and minor divisions of the same in the State. Second, to ascertain as far as possible the principal insect enemies of forest growth and their habits, as well as to study the climatic and other conditions that might be favourable or unfavourable for their multiplication; or the extension of their depredations. Third, to determine by experiments and otherwise some improved and practical method of preventing the losses that are occasioned by the more destructive kinds, especially those caused by bark and wood infesting insects.

The following descriptions of sawflies belonging to the subfamily Nematinæ include, with one exception, a number of species which have been reared from the larvæ by Mr. H. G. Dyar. Mr. Dyar is anxious to publish the descriptions of the larvæ, and the technical descriptions of the species presented herewith are made to enable him to assign his larvæ to described species and avoid the difficulties which would arise from the description of larvæ before the adult insects have been characterized. The very valuable work which Mr. Dyar is doing in rearing larvæ is resulting in the clearing up of some puzzles in the classification of insects, and has no more interesting outcome than the fact that many of his rearings, at least in the line of sawflies, prove to be of species hitherto undescribed, showing how little we really know of the insects of this group in this country. The adults of most sawflies rarely leave their food-plants, and live but a few days, and hence it is not at all to be wondered at that so many species occurring on common plants have not been taken by collectors. The collected species, in fact, are usually only those which happen to frequent flowers and those taken by random beating, which, with insects of quick flight, like many sawflies, is not a very successful method of collecting.

Liparocephalus cordicollis, Lec.—This species does not differ in any way from L. brevipennis, Mæk., except in its pale colour, and the two forms must be united, as intimated in a former paper (Can. Ent., XXIV., 158). Since the publication of that paper more than thirty examples of brevipennis and several of cordicollis have been examined and compared. Apart from colour, not a single character of general applicability has been observed by which to separate them into species. The synoptic characters given by Capt. Casey (Ann. N. Y. Acad. Sci., VII., 354) are without value otherwise than as descriptions of those of some individuals. When a sufficient number of each form is present, all the elements, without exception, tabulated by him to differentiate cordicollis exist in examples of brevipennis, and the reverse.