MICHIGAN ACADEMY OF SCIENCE. 
1G5 
Key to Genera and Species of Gryllidae. 
I. Second tarsal joint minute; hind tibiae slender, armed with spines, 
between which are minute teeth. 
Genus Oecantlius. 
1. Antennae either entirely black, or with two black marks on 
each of the first two joints, those of the basal joint conflu- 
ent at the top, the inner one the longer. 
27. fasciatus. 
2. No black marks excepting on the first two joints of the anten- 
nae, each of which joints lias two parallel marks. 
28, quadripunctatus. 
II. Second tarsal joint minute; tibse stout, armed with stout immov- 
able spines only; fore tibiae with hearing organ on both faces. 
Genus Gryllus. 
1. Pronotum not over 5 mm. wide; tegmina, ovipositor, circi, and 
legs reddish brown. 29, arenaceous. 
2. Pronotum over 6 mm. wide; all black, excepting inner side 
of hind femora; ovipositor never over 15 mm. long. 
30, pemisyluan icus. 
Genus Oecantlius Serville. 
The tree-crickets are weak looking insects, with small hanging heads, 
which taper to narrow labiae; slender legs; wings and tegmina very pale 
green or hyaline; spindle-shaped abdomens. In the female the tegmina 
are more closely wrapped about the body than in the male. They live on 
tall herbaceous plants such as golden-rod, or on bushes, on the twigs of 
which their eggs are laid. The species are distinguished by the marks 
on the first two joints of the antennae. 
27. Oecantlius fasciatus Fitcli. — Vertex and occiput arched, vertex 
sloping downward to merge into face. Antennae long, slender, very 
easily broken in the cyanide bottle. Pronotum narrower, anteriorly, 
than the head, wider posteriorly, very shallow, so that from the side 
it gives the appearance of a slender neck. Tegmina broad and fiat on 
top, overlapping the entire width of their dorsal surface; rounded at the 
apex; wings 1-2 mm. longer than tegmina. Legs very slender. 
Color: — General color, light green. Black stripe on mid-dorsal line of 
head and pronotum. Ventral side of abdomen black; sometimes other 
black stripes. Antennae are sometimes entirely black, sometimes have 
two distinct black marks on each of the first two joints, those on the 
basal joint being confluent at the top. 
Measurements: — Length of body, 12-13 mm.; pronotum, 2 mm.; teg- 
mina, 12 mm.; width of pronotum, front margin, 1.5 mm., hind margin, 
2.3 mm.; of dorsal field of tegmina, male, 5 mm. 
28. Oecantlius quadripunctatus Beutenm filler. — The shape of this 
species is the same as that of 0. fasciatus. There are no dark stripes vis- 
ible from above, though the ventral side of Ihe abdomen is sometimes 
dark. Color pale green. Antenna? with two separate black marks on 
each of the first two joints, the inner mark much longer than the outer 
one. On the basal joint, the inner mark has a small outward pointing 
hook which does not, however, unite with the outer mark. 
Measurements: — Length of body, 11-12 mm.; pronotum, 2.1 mm.; teg- 
mina, 11 mm. 
