1915] Life History Thelia Bimaculata 141 
GENERAL DESCRIPTION. 
This species of Membracide is one of the largest represen- 
tatives of the family found in New York state. The male was 
originally described by Fabricius in 1794 and no doubt received 
its specific name from the gaudy yellow fascia on the thorax. 
The female is quite different in color from the male, being of a 
sober uniform gray with occasional irregular brownish markings. 
Thelia bimaculata is the type of Amyot and Serville’s old genus 
Thelia (1843) and is one of the few remaining species now left 
in that genus. 
The species may be at once recognized by the porrect pro- 
notal horn, the longitudinal ridges of the prothorax, the sharp 
posterior process and the yellow stripes of the male. 
HABITS. 
Of all the insects which inhabit the locust none are more 
interesting or more easily observed than this large and handsome 
species of membracid. Locally they may be found in remark- 
able numbers from early spring until late autumn, and with 
their nymphs and constantly attending ants provide a most 
profitable source of study. They seem to prefer the smaller 
trees and are most abundant in rather open growths where the 
trees are young and not over twenty feet in height, and here 
they choose the lower branches and the trunk for their resting 
places. They are seldom found more than fifteen feet above 
the ground. Like most membracids they enjoy the sun and 
the most favorable collecting places are the trees in the open 
fields, along the roadsides, and at the edges of timber. They 
are seldom, if ever, seen in shady woods. The adults have the 
interesting habit of resting on the larger branches and on the 
trunk in rows of from twenty to forty individuals, ranged so 
close together that their bodies are almost touching, and almost 
invariably with the heads pointing towards the base of the 
branch, or pointing downward if they are on the trunk. Whether 
this characteristic attitude is assumed in order to increase their 
resemblance to the thorns and irregularities of growth of their 
host, would be a matter of conjecture. An idea of the number 
of individuals which may thus be found may be given by the 
fact that one field note (July 22, 1911) records the taking of 280 
adults and over 200 nymphs at one time from one small tree. 
