44 
Journal of Agricultural Research 
Vol. XXVII, No. e 
upper surface is ornamented with black dots of variable number and 
size, the variation being largely dependent on locality. Usually, in the 
eastern form, there are from 17 to 21 spots, which are more or less 
rounded. On the prothorax there are usually from 4 to 6 spots, and 
there is also one sutural spot behind the scutellum. The small mar¬ 
ginal spot is sometimes lacking, especially in western forms. The 
lower surface is black, with the exception of the head, margins of the 
prothorax, and that portion of the elytra which can be seen from below. 
The antennae and legs are also black. 
This form can readily be distinguished from all other genera of tor¬ 
toise beetles by the characters given, and from other common species 
that attack sweet potato it can be known at once by its much larger 
size, since it is one of the largest of the leaf-beetle family occurring in the 
United States. 
The full length is about one-third of an inch (8-11 millimeters) and the 
width about one-fourth of an inch (6-7 millimeters). 
Several forms of this species occur in the United States which are con¬ 
sidered to be merely varieties, races, and, in one instance, a subspecies. 
So far as known, these variants have practically the same habits, but 
some have a different distribution and all very closely resemble the form 
described above. 
SYNONYMS AND VARIETIES 
Chelymorpha cassidea Fabricius, Syst. Ent., 1775, p. 82. 
Chelymorpha argus Lichtenstein, Cat. Mus. Hamb., 1795, p. 66. 
Chelymorpha cribraria Olivier, In Enc. Meth., v. 5, 1790, p. 383; Ent., v. 6,1808. 
p. 956. 
Var. lewisi Crotch, in Proc. Acad. Nat. Sci. Phila., 1873, p. 77. 
Var. phytophagica Crotch, 1 . c., p. 77. 
Var. septendecim-punctata Say, in Jour. Acad. Nat. Sci. Phila., v. 3, 1823, p. 435. 
Subsp. geniculata Bohemann, Mon., v. 2, 1854, p. 39. 
EGG 
The egg mass (fig. 2) of Chelymorpha cassidea is most peculiar. The 
eggs are deposited normally on the lower surfaces of the leaves and 
probably elsewhere at times, since in confinement masses have been 
found on the stalks. In the field they are deposited in clusters varying 
from 16 to 28. Six masses contained 16, 17, 18, 24, 26, and 28 eggs, 
respectively. The eggs are attached to the leaf by long pedicels, the 
pedicels being fastened to the leaf surface by a considerable amount of 
glutinous substance. The eggs also adhere to each other at their bases 
and, in many cases, halfway or a little more toward the apices, but the 
ends are free and divergent. The eggs are deposited irregularly, without 
definite pattern. There is usually a central irregular row of 6 eggs, 
flanked at each side by a similar irregular row of 5 or 6, while the outer 
rows together form a mass, which is always irregular, but with a sugges¬ 
tion of a circular arrangement. 
The individual egg measures about 1.6 millimeters in length and 0.8 millimeter 
in width, being approximately twice as long as wide. It is evenly rounded at the base 
and bears at the distal end a cap which opens at one side when the larva issues and 
which bears at the extreme apex a prominent dark reddish tubercle of irregular shape, 
somewhat resembling a bit of sealing wax. The general color of the egg is dull buff 
and the surface is granulated. 
