•298 
Acanthia lectularia 
Landois acknowledges that he cannot fix any distinct function for 
the crop, and lie definitely says that it is “ not suited for creating suction 
on account of its strong sides.” Microtome sections would have showed 
him his error. He suggests that peristalsis of the gut causes the suction, 
but the great tenuity of its wall rules this out of court. 
The part of the crop to which are attached the muscles which operate 
the pump is reticulated very irregularly with lozenge-shaped papillae, the 
surface of each papilla being very coarsely rugose (Fig. 17). On the dorsal 
surface, and indeed helping to form part of its roof, and immediately 
at the base of the labium just where the “ pump ” broadens out, is the 
epipharynx. This is a triangular piece of chitin, the apex pointing to 
the anterior end. On its posterior border there is a row of very short 
delicate spines, about ten in number, which hang down into the cavity. 
When the dorsal surface of the crop is dissected off (after having been 
boiled in caustic potash) and mounted for microscopic examination, 
the spines of the epipharynx are seen quite clearly on a horizontal plane 
(Fig. 17). Since in a microtomed bug they are seen hanging down into 
the pharyngeal cavity, it would certainly suggest that they are very 
loosely articulated to the chitin plate. The waiter can offer no sug¬ 
gestion as to the function of these spines. 
Landois says that besides the epipharynx there are four other smaller 
chitin plates on the dorsal surface. 
The writer, after many dissections, would suggest that these “ chi- 
tinous plates ” are merely an optical effect caused by the remains of the 
attachments of the muscles which move the crop-roof. 
The pump needs no muscular effort to bring it back to its at rest 
position on account of its shape and the elasticity of the walls which 
are formed of stout chitin (Fig. 25). 
The function of the crop in the bug being solely that of providing 
the suction necessary for the imbibing of blood, it cannot therefore 
be used, as in other insects, for purposes of storage. Thus ingested 
blood goes directly into the stomach, and after that is filled, the first 
portion of the intestine is utilised. The stomach and intestine have 
irregularly disposed muscle bands in their walls (Fig. 28). When a 
bug has been allowed to have only a small meal and is then dissected, 
the stomach usually appears to be symmetrical and laterally lobed, or 
occasionally of an asymmetrical shape depending on the volume of 
blood which has been imbibed. When the stomach is quite full there 
is no sign of lobes at all, but (if used for storing) the first portion of the 
intestine then shows the unilateral pocketing (Fig. 28). The writer has 
