MORSE: ORTHOPTERA OF NEW ENGLAND. 227 
not only by the jaws and maxillae but by chitinous teeth or 
ridges in the walls of the gizzard (proventriadus) ; digestion and 
absorption take place in the middle part of its course. Between 
the outer tube formed bj^ the body-wall and the inner tube of the 
food-canal lie the other internal structures, — muscles, nerves, 
glands, and reproductive organs — in a cavity filled with blood, 
which is kept in motion by the pulsations of a cylindrical heart 
lying in the dorsal part of the abdomen. Immersed in a circulat- 
ing nutrient fluid, special blood-vessels to the various organs are 
unnecessary. The needs of respiration are supplied by a system 
of air-tubes (tracheae) opening externally at the spiracles and 
penetrating every part of the body and its appendages. These 
have a characteristic appearance under the microscope owing to 
the spiral or ring-like chitinous thickenings in their walls which 
hold them open, like the wire in suction hose. In Locusts, large 
air-sacs in addition serve as reservoirs in the bodj^ and connect 
with the tracheae near the spiracles. The lining of the tracheae, 
and also of portions of the food-canal, is shed at the periodical 
molts. 
For a full account of the internal anatomy the reader is referred 
to the works cited in the text under the several groups. 
Habits. 
With the dawn of consciousness the young orthopteron finds 
itself in circumstances almost as varied as the species, according 
to the location of the egg. The parent Earwig and Mole-cricket 
deposit their eggs in underground chambers excavated by them- 
selves, and are credited with helping the young to emerge and 
even with taking care of them for some time afterward. But for 
the most part survival and success in life are entirely dependent 
on the actions of the tiny, new-born individuals themselves. 
The eggs of Walking-sticks lie all winter long, seed-like, among the 
fallen leaves of woodlands; some, it is believed, for two winters. 
The young hatch in spring, clamber up the stems of the under- 
growth, and feed on the newly sprouting, tender leaves. The 
eggs of Roaches are encased in horny capsules, several in each, 
which are dropped at random in the haunts of the parent. Those 
of the Katydid are gummed to the twigs of trees frequented by 
