NKW MAr.I.(»l'HA<iA. l')5 



beliind bv sliirht constrictions. From its anterior end 

 four Malpighian tubules arise. Tbe rectum is very 

 large (plate xi, tig. 13, and plate xvii, tig. 6, /•). Its 

 anterior part is much dilated, the enlargement i>eing 

 rather suddenly narrowed in front, but posteriorly grad- 

 ually passes into the more tultular posterior part. Its 

 anterior end is provided with six oval rectal glands. 

 These vary in size in dilferent specimens. In the male 

 the anal opening is in the upper posterior part of the gen- 

 ital chamber, in the female it is in the end of the last 

 abdominal segment (plate xv, ligs. 1 and 2, a, and plate 

 xvii, tig. 6, '0- 



Sections show the following histological features of 

 the alimentary canal. The ])rc ventricular pari is lined 

 with a ehitinous intima continuous with the body-cov- 

 ering at the mouth. The ventriculus lacks an intima, 

 but possesses a thick inner cellular epithelium (plate x, 

 tig. 1, >•). The intestine has a thin ehitinous lining 

 continuous with the body-covering at the anus. The 

 prerectal part possesses a thin cellular epithelium cov- 

 ered by an outer membrane, surrounding which are 

 small muscle libers. The rectum lacks the epithelium 

 and has larger muscle hbers (plate xvii, tig. 0, rtm). 

 The rectal glands project inwardly and are covered by 

 the ehitinous lining of this part of the alinientary 

 tract. 



In the Ischnocera, as before stated, the alimentary 

 canal is complicated bv a verv remarkable condition of 

 the crop. This in the genus Triclioilcctes has the form 

 of a larsje sac connected with the lower end of the 

 tesophagus by a long, narrow neck; in the other gen- 

 era it forms a large transverse dilatation of the a^soph- 

 agus, some distance above where the latter «)pens into 

 the ventriculus. The crop is always produced much 



