ON THE LIFE HISTORY OF UGIMYA. 13 



segments of the abdomen. 



I may here add some observations on the digestive canal, and 

 respiratory and nervous systems. Of the digestive canal ( Fl. II, ßg. 

 11 ), the proventriculus ( & ) is an oval muscular walled sac, and at the 

 part where the oesophagus (a) opens into it, there is inserted the duct of 

 the sucking stomach ( c ). The latter is a long slender tube having a 

 bilobate thin-walled bladder-like sac at its end. The chylific stomach 

 (<^) is a long convoluted tube, and at the junction of it with the ileum 

 open two malpighian vessels ( e ), of which each is divided into two 

 long twisted branches. The chylific stomach is immediately followed 

 by the ileum (/) and rectum (re) The rectum consists of a so-called 

 " Rectaltasche " (/t) and a short " Ausmündungstück " as A. Weis- 

 mann C') has called them in Musca vomitaria. The "Rectaltasche" is a 

 thick- walled chamber, on each side of which there are found two horny 

 white tubercles ( Rectalpapilleii, g ). Each of these is slightly de- 

 pressed at the tip, and from this depression there arise several fine air- 

 tubes which are really branches of a trachea which opens at the spiracle 

 on the third segment of the abdomen. The base of the tubercles, which 

 is converted into a long pointed process, projects into the interior of the 

 " Rectaltasche." Finally the rectum, passing posteriorly along with 

 the common tube of vasa deferentia or vagina, ends at the anus. This 

 opens on the dorsal side of the clasper in the male (P/. II, fig. 1 g;fig- 

 2a), while in the female it ( PL II, fig. 4h) opens on the ovipositor, 

 separated however from the opening of the vagina ( FL II, fig. 4 a) by 

 two chitinous plates ( FL II, fig. 4 c) placed side by side. 



Respiratory system (P/ II, fig. 12) consists of a number of air- 

 sacs and tubes. There are four pairs of air-sacs in the head, two in the 

 thorax and one in the abdomen. Of the four pairs in the head one 

 (a a) occupies the base of the antennas, two (hh', cc') the base of the 



(7) A. Weismann loc. cit. p. 300. 



