May, 1916] Homopteroiis Studies. Part II 315 



Internal Anatomy. 



The Digestive System. (PI. XXI, Fig. 22; PI. XXII, Fig. 34). 



The chitinous pharynx passes back into the membranous 

 esophagus (e. s.), which is a relatively short simple tube. 

 In the metathorax, where the esophagus enters the midintestine, 

 a constriction is noticed and a large food reservoir is developed. 

 The latter structure is comparable to the food-reservoir of 

 certain Fulgoridas and Cercopidae. The food-reservoir is a 

 bilobed or double U-shaped structure, which opens into the 

 intestinal coils; its function is probably that of a storage reser- 

 voir. From the reservoir the alimentary canal continues as a 

 long, convoluted tube (m. i.) of small diameter; the length of 

 midintestine is about two and a half times that of the body. 

 It ends in the short rectum without differentiating into either 

 colon or ileum. The rectum continues to the anus, which is 

 located on the dorsal surface of the last abdominal segment. 



Opening into the midintestine (m. i.) are the long Malpighian 

 tubules (mp. t.) ; these are difficult to detect in the Jassid, but 

 at length may be seen among the coils of the intestine. They 

 are about the same length as the body and are of small diameter. 

 There are only two pairs so far as was observed. 



The food reservoir (f. res.), or crop, in Deltocephalus 

 inimicus occurs entirely within the abdomen and does not enter 

 the thorax. This seems to be the general condition, although 

 in some forms it is to be found penetrating the thoracic region 

 In some forms it occupies a great part of the anterior region 

 of the abdominal cavity. 



The digestive system may be readily dissected out of 

 preserved specimens, although some little difficulty is exper- 

 ienced in keeping the coils , of the intestine intact. It was 

 noticed that in specimens which had been cleared in carbol- 

 turpentine, there w^as a tendency on the part of the food 

 reservoir to swell up and telescope through the dorsal wall of the 

 abdomen. 



The opening of the alimentary canal to the exterior, i. e., 

 at the anus, is on the last abdominal segment and in the majority 

 of individuals examined it was noticed that the anal orifice was 

 beset with hairs and strong spines. The anal tube is a small 

 structure, which is heavily chitinized. It conveys the feces to 

 the exterior. In most individuals the anal tube is two-jointed, 

 the basal joint being the longest. 



