195 



known spume or froth in which the nymph lives. And, according 

 to Berlese's theory, the sécrétion of the glandular portion of the 

 tubes is diluted by osmosis, through their zigzag portion in the 

 filter-chamber, of water from the food imbibed. Neither the 

 ventricle nor the urinary tulies make a large number of zigzags 

 within the filter-chamber of the Menibracid, but merely form a few 

 twists; yet thèse twists présent a fair surface to the ephithelial wall 

 of the crop and resophagus, and a 

 large amount of osmosis will take 

 place, if the filtration theory is cor- 

 rect. According to Berlese, somewhat 

 similar arrangements of the digestive 

 tube occur in Coccidae (Gli Inselti. 

 volume primo, pp. 733-4, 1909.). 



Ten abdominal segments eau be 

 counted in the adult maie and female, 

 or reckoning the anal ring as a 

 segment, eleven. In the nymphs the 

 segments can be even more easily 

 discerned. The last abdominal seg- 

 ments of the nymph (as is usual 

 amongst the Memhracidae) can be 

 very rapidly exserted from or with- 

 drawn into the ninth segment. This 

 is rendered possible by the very great 

 development of the intersegmental 

 memhra.ne{irnh, Figs. 3and4)between 

 the ninth and tenth segments, and 

 also by the great development of the 

 ordinary intersegmental muscles {im) 

 between the same segments, as well 

 as by their extensive innervation. In thefemale nymph the mem- 

 brane between the eighth and ninth segments, and the anterior 

 part of the ninth segment, bear the génital armature, the succeeding 

 or tenth segment being a long tube of small diameter, black and 

 chitinous and bearing at its pos- terior extremity the invaginated 

 anus (an), which can beeverted by blood pressure. The invaginable 

 portion is membraneous, but the actual anal orifice is formed by a 

 slender chitinous ring, which may be regarded as the eleventh 

 segment. The inner surface of the mem braneous portion is 

 minutely grandular, and during life distinctly of a red color [In a 

 Ghinese species of Membracid the glandular portion extends along 

 the intestine and is of a bright red; the last (tubular) segment is 

 hyaline at its mid-part though black elsewhere, so that the red 



Fi g. 4. 



