1815.]} ‘On the Uses of the Dorsal Vessel. 37 
corcelet have a shade of red. The stigmata of this species placed 
upon the inferior sides of the abdomen are rounded and bordered by 
a salliant fold of the coreaceous envelope. / 
Several of the orthopteres exhibit at once arterial and pulmonary 
trachee, Of this number are the forficula, blatte, phasmes, 
mantes, achetes, locust, mole crickets. But as these tracheze are 
not similar in different genera, and as their complication is not 
quite the same, we shall make them known in those in which it 
presents the greatest peculiarity. 
The respiratory organs of the forficule and blatte present little 
difference. They are composed of a system of arterial trachez 
formed by a common trunk, which extends from one extremity of 
the body to another, ‘and into which transversal tracheze pass, which 
are distributed in a great number of parts, In the head ;iey furnish 
the ramifications to the principal muscles, especially to the adduc- 
tors and abductors of the mandibles and oesophagus. They then 
extend in the corcelet by two principal trunks which lie below the 
pulmonary trachea, but which soon divide, giving out numerous 
ramifications to the muscles of the corcelet, to the intestinal tube 
and the first pair of legs. The principal trunks continue to the 
thorax, keeping on the sides of the body. They then send a pretty 
large branch, which passes into the opening of the tremaer, to take 
up the air which other ramifications distribute in the muscles con- 
tained in the thorax, and in those of the wings and legs. It aps 
peared to me that the arterial trachez furnished in the corcelet and 
thorax branches which spread in the legs, where they give out a 
rauch greater number of ramifications than the pulmonary trachece, 
which equally make their way thither. The trunks of the arterial 
tracheze communicate with those of the pulmonary trache by 
lateral branches proceeding from the internal sides of these trache. 
The same thing takes places in the corcelet, the thorax, and abdo- 
men, ‘The same trachee form round the stomach and its append- 
ages nets of tracheze quite inextricable. 
The arterial trachez, after having given numerous ramifications 
m the thorax, extend themselves in the abdomen by a common 
trunk, which opens into the six stigmata placed on the sides of the 
body. It is likewise near these stigmata that the common trunks 
furnish each two bundles of transversal trachew; so that there are 
24 such bundles in the abdomen. ‘These same trachee make all 
the parts enjoy the impression of the air, distributing themselves 
over the intestinal viscera, the organs of generation, and the abdo- 
minal muscles. I must observe that the communication of the 
arterial and dorsal trachewe takes place by means of transversal 
branches, which the first send off at intervals to the second. 
The pulmonary trachea: appear equally in the head, where they 
extend round the superior portion of the cerebriform ganglion and 
round the eyes, whether single or compound. 'lhey give out but a 
small number of ramifications in the head ; and passing through the 
superior portion of the occipital foramen, they go to the corcelet, 
