64 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 68 



Garman (1891) reports that the males of the cricket, Hadenccrus 

 subterraneus, protrude a pair of white, fleshy appendages from shts 

 between the ninth and tenth abdominal terga. He thinks that these 

 appendages are protruded only during the period of sexual ex- 

 citement. 



Minchin (1888) describes a new organ in Periplaneta orientalis. 

 This organ consists of a pair of shallow, lateral pouches near the 

 median line in the articular membrane between the fifth and sixth 

 abdominal terga. The pouches are covered with the fifth tergum, but 

 connect with the exterior by a pair of slit-shaped openings. These 

 pouches contain numerous, stiff and branched hairs, and just beneath 

 the chitinous lining of the pouches lie unicellular glands which 

 extend into the enlarged bases of the hairs. He thinks that probably 

 the secretion from these cells runs into the hairs which serve as a 

 means of diffusing the odor. The same author (1890) describes a 

 second glandular organ in the same species. This organ consists of a 

 pair of tubular ducts which lie just above the pouches of the first 

 organ, and they open to the exterior through apertures near the 

 slitlike openings of the pouches. 



Krauss (1890) observed in the roach, Apldcbia hivittata, invagina- 

 tions whose common exit may be seen on the seventh abdominal 

 tergum. These invaginations are filled with hairs. 



Oettinger (1906) describes the scent-producing organ in the roach 

 Phyllodromia germanica, as two double pouches, one of which is 

 located in the articular membrane between the fifth and sixth, and the 

 other betwen the sixth and seventh abdominal terga. They are found 

 only in the sexually matured males. Each pouch is a double invagina- 

 tion, being divided in the median line by a tonguelike partition, and 

 muscles are attached to the walls of the pouches. When the muscles 

 contract the lumen of the pouch is constricted whereby the secretion 

 is forced to the exterior. Beneath the chitinous lining of the pouch 

 lies an irregular layer of supporting cells. The layer next to the 

 abdominal cavity is composed of long, cylindrical and extremely large 

 gland cells, each of which has a reticular netlike contents and a con- 

 spicuous nucleus having several nucleoli. A secreting tubule arises 

 near or even against the nucleus, pierces the contents of the cell and 

 runs to the lumen of the pouch. The gland cells as usual are modified 

 hypodermal cells. In Periplaneta orientalis the pouch is lined with 

 hollow hairs into which the secreting tubules of the unicellular glands 

 run. He thinks that these organs bear a close relation to the sexual 

 behavior of these insects. 



