320 



LEPIDOPTERA 



slender oesophagus through the length of the thorax, dilating when 

 it reaches the abdomen to form a tubular stomach ; before this 

 it is somewhat enlarged to form an indistinct crop, and gives off 

 a large diverticulum usually called a sucking stomach. According 

 to Burgess, this structure does not possess the function ascribed 

 to it by this name, and he terms it a food-reservoir. The Mal- 

 pighian tubes are six in number, three on each side, and each set 

 of three unite to form a common tube opening into the posterior 

 extremity of the stomach ; behind them the alimentary canal 

 continues in the form of a slender, tortuous intestine, expanding 



FIG. 163. Internal anatomy of Lepidoptera. Section of the body of a female butterfly, 

 Anosia plexippns. (After Scudder.) The portion to the left of the vertical line 

 more magnified. I. II. III. thoracic segments ; 1-9, abdominal segments ; , 

 antenna ; a, anus ; ac, aortal chamber ; ay 1 , etc., abdominal ganglia : agl 1 , agl-, 

 accessory glands ; ao, aorta ; br, brain ; c, colon ; cp, copulatory pouch ; ex 1 , ex' 2 , 

 ex 3 , coxae ; fr, food-reservoir ; g l , suboesophageal ganglion ; h, dorsal vessel ; i, 

 intestine ; Im, area filled by wing muscles ; I. or, ovary, or egg-tubes of left side ; 

 mv, Malpighian tube (the two others of the right side cut away, except small por- 

 tions) ; mx, maxilla ; o, oviduct ; oo, its orifice ; oe, oesophagus ; ov.c, end of left 

 ovary ; p, labial palp ; ph, pharynx ; r.ov, terminal parts of right ovarian tubes, 

 turned to one side, after the tubes have been cut away ; sd, salivary duct ; sgl, 

 salivary gland ; sp, spermatheca ; st, stomach ; tg, thoracic ganglia ; v, copulatory 

 orifice. 



at the extremity of the body to form a rectum. The dorsal or 

 circulatory vessel commences near the posterior extremity of the 

 body, but in the front part of the abdomen is deflexed to pass 

 under the great phragma into the thorax, where it rises abruptly 

 to the dorsal wall, but is again abruptly deflexed, forming a loop, 

 and is then prolonged above the oesophagus into the head : at 

 the summit of the thoracic loop there may be a dilatation called 

 the aortal chamber. The supra- and infra-oesophageal ganglia 

 are consolidated into a mass pierced by the oesophagus : there is 

 a minute frontal ganglion ; the ventral chain consists of three 

 much approximated thoracic ganglia and four abdominal ganglia 

 separated from the thoracic by a long interval. 



