COCKROACHES. t 
they present, however, a very anomalous and peculiar habit. The 
eggs, instead of being deposited separately, as with most other 
insects, are brought together within the abdomen of the mother into 
a hard, horny pod or capsule which often nearly fills the body of the 
parent. This capsule contains a considerable number of eggs, the 
number varying in the different species, arranged in two rows, the 
position of the eggs being indicated on the exterior of the capsule by 
transverse lateral impressions. When fully formed and charged with 
eggs the capsule is often partly extruded from the female abdomen 
and retained in this position sometimes for weeks, or until the young 
larve are ready to emerge. The cap- 
sule is oval, elongate, or somewhat bean 
shaped, and one of its edges is usually 
serrate. The young are in some in- 
stances assisted to escape by the par- ; 
ent, who with her feet aids in splitting Pee eri eater Li 
the capsule on the serrate edge to fa- indicated by outline figure. (Author’s 
cilitate their exit. On hatching, it is 9 ""™""™) 
said the young are often kept together by the parent and brooded 
over and cared for, and at least a colony of young will usually be 
found associated with one or two older individuals. These insects 
are more or less gregarious, notably so in the case of the black beetle 
of Europe and to a less extent with the German and American 
roaches. 
They pass through a variable number of molts, sometimes as many 
as seven, the skin splitting along the back and the insects coming 
out white, soft, but rapidly hardening and assuming the normal 
color. Some astounding statements have been made as to the length 
of time required for the development of the roach from the egg to 
the adult. Four or five years have been said to be necessary for an 
individual to reach full growth; but more recent breeding experiments 
have not altogether confirmed these statements. Their develop- 
ment, however, is unquestionably slow, and probably under the most 
favorable conditions rarely is more than one generation per year 
produced. In colder countries the breeding and growth are practi- 
cally restricted to the warm season. During the winter months 
they go into concealment and partial hibernation. Blattella ger- 
manica has been shown to reach full growth in a variable period of 
from four and a half to six months.1_ The common American roach ? 
has been carried from the egg to the adult state in the insectary. 
Young hatching July 11 from an egg case received from Eagle Pass, 
Tex., reached the adult stage between March 14 and June 12 of the 
following year, indicating a period of nearly 12 months for complete 
development. The rate of growth of the roach undoubtedly depends 
1 Hummel, Essais Entomologiques, No. 1, St. Petersburg, 1821. 2 Periplaneta americana L. 
