1S64.] 
399 
gins of four basal segments, cinereous, that on the second segment 
slightly interrupted in the middle ; fifth segment cinereous, with the 
depressed space small and silvery in certain lights ; beneath brown- 
black, disk of second segment stained with rufous, and the apical mar¬ 
gins of the segments obsoletely fringed with cinereous. Length 3 lines. 
Ilab. —Massachusetts. One specimen. Coll. Mr. F. Gr. Sanborn. 
Rather smaller than E. variegatus of Europe, and marked somewhat 
like E. donatus Smith, but distinct from any described species. 
Gen. CCELIOXYS, Latr. 
Head as wide as the thorax ,• the ocelli placed in a triangle on the vertex; 
the eyes lateral, elongate, and covered with pubescence. The labial palpi fonr- 
jointed, the basal joints elongate, the second rather longer than the first, the 
third and fourth minute, placed at the side and near the apex of the second 
joint. Tho; maxillary palpi three-jointed, the basal joint very short, thick and 
subglobose; the second joint not so thick, but of about the same length; the 
ajjical joint of equal length, but slender and cylindric. The labrum elongate, 
transverse at the base and produced at the lateral angles Thorax globose, the 
scutellum armed with a tooth on each side; the superior wings with one margi¬ 
nal and two submarginal cells; the marginal cell narrow, elongate, and round¬ 
ed at the apex; the second submarginal cell receiving the two recurrent ner- 
vures, the first near its base, and the second near its apex. Abdomen conical, 
acute at the apex in the females; in the males the apex is dentate. The 
clavjs simple in the females; in the males bifid at their apex. The males have 
their anterior coxse toothed.”—Smith, Bees of Great Britain, p. 144. 
These bees are parasitic on the genus Megacliile. They are easily 
known by their conical abdomen, which is acute at tip in the females 
and armed with spines in the males. They are generally black, strongly 
punctured and having the abdominal segments fringed with white 
pubescence j the scutellum is produced, posteriorly and armed on each 
side with a short or long, stout tooth, and the segments of the abdo¬ 
men, in most species, have a more or less deep transverse impressed 
line on their middle. 
In separating our species, I have used Dr. Nylander’s excellent spe¬ 
cific characters, i. e., the form of the anal plates of the 9 abdomen; 
the upper and lower plates difler in shape and are constant in each 
species; the inferior plate is more or less longer than the superior, 
being in some species only slightly longer, and in others nearly half 
as long again. The males are very difficult to determine, and their 
habits will have to be studied well before they can be correctly separated. 
