MICHIGAN ACADEMY OF SCIENCE. 
149 
from April to early July, depending on the species and the climate, 
hatching in about three weeks. The color and markings of individuals 
are of little use in distinguishing species because there is so much varia- 
tion within the species. 
Dr. J. B. Hancock describes twenty-one genera, only five of which are 
found in north-eastern United States. Of these, three were found at 
Douglas Lake. 
Key to Genera and Species of Tettigidae. 
I. 
II. 
Anterior femora carinate above. Antennae 12-14 joints. 
1. Dorsal front margin of pronotum truncate, not produced 
upon head beyond posterior margin of eyes. 
Genus, Tettix. 
a. Eves small, vertex about the width of one eve. 
2, ornatus. 
1). Vertex about twice the width of one eye. 
3, acadicus. 
■ 2. Dorsal front margin of pronotum ungulate, produced in front 
of posterior margin of eyes. 
Genus, Nomotettix. 
a. Shallow fossa on each side of median carina of ver- 
tex. Face strongly retreating, body not over 7 
mm. in length. 
4, parvus. 
1). Deep fossa on each side' of anterior part of median 
carina of vertex. 
(a) Median carina of pronotum strongly com- 
pressed, translucent, punctate. 
5, compressus. 
(&) Median carina of pronotum low, only 
slightly arched. 
6, cristatus. 
( c ) Pronotum strongly arched and strongly ad- 
vanced upon head. 
7, arcuatus. 
Anterior femora sulcate above. Antennae 16-22 joints. 
1. Lateral carinae present in front of shoulders. Distribution 
United States. 
Genus, Tel tig idea. 
a. Antero-dorsal margin of pronotum obtuse, vertex de- 
cidedly wider than one of the eyes, wings and 
pronotum extending beyond posterior femora. 
8, parvipennis pcnnata. 
Genus Tettix Charpentier. 
Dr. Hancock, who describes twelve species and as many more vari- 
eties, says: “The tendency to vary is inherent in all the forms, the line 
of demarkatioh not easily drawn between species. * * * The descrip- 
tions of the species give a composite conception to the mind, the varia- 
tions being of such wide range as to baffle separate description of each 
individual phase.” 
