4 Henuptera-Heteroplera. 
number, but in Nepa as many as six; the cesophagus 
passes through the thorax as a straight tube, distending at 
the base of the abdomen into a “broad, bladder-shaped, 
generally long and often irregularly folded stomach Be 
this is not a sucking stomach, according to Burmeister, but 
is the first of several successive stomachs, and is, he says, 
without doubt, analogous to the crop of the Coleoptera and 
Orthoptera. The second stomach is “ generally the narrowest 
and always the longest,” and in function and structure 
seems to correspond to the proventriculus, although it has 
not the horny structures observable in the mandibulata ; at 
its posterior end it is distended, in a bladder-like fashion, 
beyond this again follows, in many of the genera, a third 
stomach, whose cavity in some genera is formed by four 
half-cylindrical tubes; in many, however, this third 
stomach is wanting, but in compensation the second 
stomach and other following intestines are longer; the 
duodenum and ilium are, according to Burmeister, practi- 
cally wanting in the bugs, so that the stomach opens 
directly into the colon, which is terminated by the apical 
opening of the abdomen; the urinary vessels discharge 
into the stomach near its posterior extremity. 
The Nervous System, according to Packard, consists of 
the cephalic gangha and two thoracic gangha, of which 
the anterior is the smaller, which send off two main trunks 
to the abdomen. 
The Circulatory System, as in other insects, consists of a 
dorsal vessel or heart, from which the blood circulates 
through the blood vessels by the pumping action of the 
contractions and dilatations of that organ. 
The Respiratory System is conducted through the agency 
of spiracles, which are orifices in the external surface of 
each segment, from which the trachez distribute the air 
through the system; these spiracles may be plainly seen 
when on the underside of the abdominal segments, and in 
most of the Pentatomidz they are black. “In Nepa and 
