496 MEDICAL ENTOMOLOGY 



subapical portion light, a black spot in the centre, and another at the 

 apex. Connexivum ochraceous with black spots. Ventral portion 

 brown; dark legs brown; tarsi light brown. Length 18 mm.; breadth 

 7 mm. From Texas. Its habits are unknown. 



INTERNAL ANATOMY OF CONORHINUS 



The internal structures of Conorhinus rubrofasciatus are simple and 

 easy to recognize. The alimentary canal shows the usual divisions, and, 



like that of the bed bug, to be described presently, is 

 The alimentary canal r , . . . r , -, . . ,. 



remarkable for the low insertion of the Malpighian 



tubes. The pharynx (Plate LXIV, fig. 5) is elongate, corresponding 

 with the shape of the head, and is boat-shaped, the anterior end being 

 much narrower than the posterior. It consists of two chitinous plates, 

 of which the ventral is the stoutest and most strongly concave ; the 

 dorsal plate fits inside the ventral one and is in apposition with it in 

 the position of rest, but can be pulled away from it by a series of 

 strong dilator muscles, which pass from its dorsal surface upwards and 

 outwards to the inner surface of the wall of the head cavity. The 

 oesophagus emerges from the posterior end of the pharynx as an 

 extremely delicate tube, and passes through the neck and the thorax. 

 At its termination the thickness of the wall of the gut is greatly 

 increased, and the wall itself thrown into a number of thick folds 

 (Plate LXII, fig. 10), forming a prevent riculus, a structure which is 

 absent in the bed bug. The epithelium at this part is composed of 

 columnar cells. The mid-gut commences as a saccular swelling of con- 

 siderable size, equal to about one-fourth the total length of the 

 alimentary canal. In the resting condition the lumen is occupied by 

 a collection of small bubbles of gas, with a considerable amount of 

 a reddish brown pigment ; immediately after feeding the chamber is 

 greatly distended with fresh blood, which is strictly limited to this 

 swollen part of the gut. As digestion proceeds the colour darkens 

 and the contents come to have a thick treacly consistence. Posterior 

 to the saccular portion of the gut the lumen is very much constricted, 

 and always contains a large amount of black debris. The tube is con- 

 voluted and situated mainly in the posterior part of the abdomen. The 

 rectum is very sharply marked off from the rest of the gut by its creamy 

 white colour. It is pear-shaped, with the broad end directed forwards, 

 and is marked throughout its surface with numerous coarse striations, 

 indicating the course of the circular bundles of muscles fibres in its wall. 



