350 EENEST WARREN. 



Heart. — A long, dorsal, uniform vessel lying in a special 

 blood-space occurs; it can be traced from the posterior surface 

 of tlie procerebral lobes to the hinder region of the abdomen ; 

 no specially dilated portion appeared to be distinguishable 

 (PL XXI, fig. 92). 



Alimentary Canal. — Labrum setose, mouth small, 

 pharynx and sucking pharynx essentially similar to those of 

 the imago. The oesophagus is short and narrow throughout, 

 thus differing from that of the imago in not gradually dilating 

 as it passes backwards. There is a small oesophageal valve. 

 The mesenteron commences in the middle of the prothorax 

 (PI. XXI, fig. 92), while in the imago it begins in the 

 posterior part of the metathorax. The mesenteron of the 

 larva extends through only two abdominal segments, while 

 in the imago it runs through about six. 



As in the imago, there are no signs of ctecal glands in the 

 mesenteron. 



The ileum in the larva is narrow and relatively long, 

 extending through three segments. At the junction of the 

 ileum with the mesenteron there open dorsally into a little 

 pouch two pairs of Malpighian tubes (PI. XXI, figs. 92 and 

 93, e. ml.) ; the width of the tubes at their ends joining the 

 gut is very conspicuously narrower than distally, and such is 

 also the case in the imago. In the imago only two tubes 

 joining the gut could be found. In the case of a male imago 

 Paracorotoca, the junctions of the tubes with the gut were 

 so excessively attenuated that there is even reason to speculate 

 whether an appi-eciable functional aperture was really present. 

 It is just possible that some of the nitrogenous waste is 

 permanently stored in the swollen cells in the distal portions 

 of the Malpighian tubes. 



The colon and rectum are relatively short in the larva. In 

 the imago the colon is very large, and replaces the greater 

 part of the ileum of the lai"va. 



In the ventral wall of the rectum near the anus there is 

 a prominent projection covered by an exceptionally high 

 ectodermal epithelium (PI. XXI, fig. 92, a.e.o.). Special 



