Prof. Westwood and others confused these wasps with the Vespidæ and the Eumenidæ, although Latreille had years previously established his family Masarides. Henry de Saussure, in his “Etudes,” treats them as a tribe. They, however, represent a distinct family close to the Eumenidæ but easily separted from them and the Vespidæ by the wings not being folded longitudinally, by peculiarities of the antennæ, which are usually strongly clavate at tip; by the wholly different abdomen, the venter being flatter; and by the much larger scutellum.

Of the habits of the Masarides nothng seems to be positively known. Some years ago Dr. Dyar gave me specimens of Masaris vespides, Cr., bred from what I take to be the nest of an Odynerine, taken in Arizona.

The first attempt to separate the species given under Coccus in the 10th edition of the Systema Naturæ of Linneus, was made by Geoffroy, in his Histoire Abregée des Insectes, Vol. 1. (1762), where he placed a part of them under Chermes and left adonidum and phalaridis, with his new species ulmi, under Coccus. Of these species only phalaridis was given under the genus Coccus by Linneus in his 10th edition, and is therefore the only species that could be regarded as the type of Coccus so far as Geoffroy is concerned.

The specimens on which this paper is based are in the collection of the University of Nebraska, unless otherwide stated. Especial acknowledgments are due to Prof. Cockerell for specimens and suggestions, to Prof. Titus for specimens, and to Prof. Bruner for overseeing my work.

Halictus Montanus, n. sp. –Female: Black, head closely coarsely and deeply puncutred on the vertex, coarser along the inner orbits, less closely on the face below the antennæ clypesu sparsely and more coarsely punctured, fringed with golden hair at the apex; mandibles black, reddish at tips; antennæ black flagellum dark brownish beneath towards tip; pubescence of head and thorax griseous, slightly tinged with ochraceous on the thorax, thin on the disc of mesothorax, dense on pleura and cheeks; thorax closely and rather coarsely punctured; base of metathorax enclosed and finely rugose, truncation finely roughened and with large punctures; tegulæ large, testaceous, and with punctures anteriorly; wings slightly yellowish, clouded apically; nervures and stigma bright testaceous; legs black, tarsi and hind tibiæ behind ferruginous; pubescence of legs slightly ochraceous, on inner side of tarsi and hind tibiæ golden; inner hind tibial spur with many short blunt teeth; abdomen black, very finely punctured, apical margins of segments with yellowish-white hair bands, bases of segments 2–4 also showing slight hair bands; pubescence at base of first segment griseous, on discs of other segments black, not showing plainly except from the sides. Length, 12–14 mm.

Macrocera immaculata, n. sp. – ♂ ♀. Head yellow, vertex brownish; antennæ dark brown, the two basal joints yellow. Thorax dark yellow, with the anterior margin and humeri light yellow. Abdomen dark brown, shining, with a wide yellowish posterior margin on each segment. Legs yellow, slightly brownsish at the tips of the femora, tibiæ and tarsi; legs and abdomen in the male with fine black hairs, which are less conspicous in the female. Wings yellowish hyaline, with a slight brownish stigma and very fine hairs. Length of body 5 mm., the antennæ and posterior legs each about double the length of the body.

In connection with the study of the pollination of flowers by insects, for several years and in several journals I have published notes on the local Halictinæ, with descriptions of new species and the missing sexes of some which were only known in one sex. This paper is intended to bring my results together in a brief form.

The so-called genus Halictus of authors seems to be altogether too heterogenous. I restore Lasioglossum and propose two other new genera. I think that the several genera must stand or fall together. The venation shows that Agapostemon and Augochlora are more closely related to Halictus, as here limited, than are Lasioglossum, Evylaeus and Chloralictus.