926 
Journal of Agricultural Research voi. xxiii, no . n 
These free-living larvae can exist in soil for several months, during 
which time experiments have shown them to be apogeotropic and posi¬ 
tively phototropic, rheotropic, pedotropic, 4 and xenotropic. * 6 Within 
the limits of the vernal temperatures of arable soils in subtemperate 
regions, the larvae are positively thermotropic. Once dried they die. 
From what has been previously said concerning the deposition of the 
eggs, it will be seen that these tropisms tend to bring the larva to the 
surface of the ground and into contact with its host. 
The entrance of the larva into its host, although very easily brought 
about in the laboratory, has not been observed in nature and doubtless 
will be a matter very difficult of observation. The forecast is that the 
larvae will come to the surface of the ground in late spring, leave the 
soil, lurk among the decayed and living vegetation near the surface of 
the ground, and enter the host mostly at night. 
The bobtailed parasitic larva, 25 by 700 microns, grows at a rapid rate, 
often increasing a millionfold in two to three months. 
BRIEF GENERIC AND SPECIFIC DIAGNOSES 6 
Agamermis Cobb, Steiner, and Christie n. gen. 
Mermithidae with terminal mouth, no mouth papillae, 6 head papillae, vagina 
S-shaped, 2 spicula; parasitic larva decaudate. Moults once in the egg. 
Agamermis decaudata Cobb, Steiner, and Christie n. sp. 
Characters as given on pages 924-926 herein, and as shown by Hagmeier's figures 
(except fig. 14) for his Merrnis albicans (3). Amphids, however, varying somewhat 
from those figured by Hagmeier; no cervical papillae seen. Moults once in the egg. 
literature cited 
(1) Cobb, N. A. 
1919. TETRADONEMA PLICANS NOV. GEN. ET SP., REPRESENTING A NEW FAMILY, 
tetradonematidae found parasitic in larvae of the midge-insect 
sciara coprophila lintnER. In Jour. Parasitology, v. 5, p. 176- 
185, 7 fig. 
(2) Glaser, R. W., and Wilcox, A. M. 
1918. ON THE OCCURRENCE OF A MERMIS EPIDEMIC AMONG GRASSHOPPERS. In 
Psyche, v. 25, p. 12-15, pi. 1. 
(3) Hagmeier, Arthur. 
1912. beitrage zur kenntnis der mermithiden ... In Zool. Jahrb., Abt. 
System., Geogr. u. Biol. Thiere, Bd. 32, p. 521-612, pi. 17-21. Litera- 
turverzeichnis, p. 595-596. 
(4) Leidy, Joseph. 
1904. researches in helminthology and parasitology. Smiths. Misc. 
Collect., v. 46, no. 1477, 281 p., illus. Bibliography, p. 249-273. 
(5) Meissner, Georg. 
1854. BEITRAGE ZUR ANATOMIE UND PHYSIOLOGIE VON MERMIS ALBICANS. In 
Ztsehr. Wiss. Zool., Bd. 5, p. 207-284, pi. 11-15. Bibliographical foot¬ 
notes. 
1855. BEITRAGE ZUR ANATOMIE UND PHYSIOLOGIE DER GORD1ACEEN. In Ztsehr. 
Wiss. Zool., Bd. 7, p. 1-44, pi. 1-7. Bibliographical footnotes. 
(7) Rauther, Max. 
1906. BEITRAGE zur KENNTNIS VON MERMIS ALBICANS V. SIRB ... In Zool. 
Jahrb., Abt. Anat. u. Ontog. Thiere, Bd. 23, p. 1-76, 3 pi. Literatur- 
verzeichnis, p. 69-72. 
(8) Steiner, G. 
1919. DIE VON A. MONARD GESAMMELTEN NEMATODEN DER TlEFENFAUNA DES 
NEuEnburgERSEES. In Soc. Neuchateloise Sci. Nat. Bui., v. 43, 
p. 142-240, illus. 
4 iri 5 o,/«— soil. 
6 £kvos= host, 
• Full descriptions will be published later. 
