pj n((<>i>(i nisitex. 525 



in the life-history of the itch-mite of llie pigeon. There is 

 found in this case, a deviation from the normal metamorphosis, 

 inasmuch as this additional stage, or "hypopial nympha " is 

 introduced between the second stage or normal " nympha " 

 and the young adnlt. The " hypnpial nymplia " is formed 

 from the normal "' nympha," acrording to Megnin, under con- 

 ditions in which there is an undue lack of nourishment or 

 ^\armth in the feathers on which the adult lives. The " hypo- 

 pial nympha " then passes down from the surface of the body 

 through the feather follicles into the connective tissues below, 

 where it lives by absorption from the surrounding tissues until 

 such time as it may safely return to the surface and become 

 changed into the aduit form. According to Michael (1884, 

 p. 390), the formation of this " hypopial nympha," in some 

 forms at least, takes place quite " irrespective of adverse con- 

 ditions,'' and only in the case of a few individuals, being " u 

 provision of nature for the distribution of the species," in 

 other words, simply a protective travelling dress. It would 

 seem, however, that in the case of the " hypopial nympha " 

 herein recorded, Megnin's conclusions are more probable. This 

 is, so far as I have been able to find, the first record of the 

 existence of this form in Australia, though it is evidently 

 well known in Europe, and is also found in the United States 

 of America (v. Ilassall). 



Host. — Pigeon : in connective tissue around roots of pectoral 

 blood vessels, and on ihe pericardium around entrance of in- 

 ferior vena cava. 



Locality. — Melbourne, Vic. : September, 1908, ])er Dr. T. S. 

 Hall. 



BIlUJUGl'vAPHY. 



Braun. — " Animal Parasites of Man," 190G. 



Bronn. — Klassen und Ordnungen des Thier-reichs ; iv., la, 



Trematodes ; iv., lb, Cestodes. 

 Cobb.— Agricultural Gazette, New South Wales, vol. ii.. 1891. 



p. 6U. 

 Cobbold.— " Entozoa," 1864. 

 Cobbold.— Proc. Zool. Soc, 1865. 



