Ottawa, for the vast amount of tick material he collected during his employment at the Kamloops laboratory, for the loan of tick specimens from the Canadian National Collection of Insects, and for his inspiration and assistance in the preparation of the manuscript. Others who at the Kamloops laboratory collected material or otherwise added to the knowledge of the ticks of Canada are the late Mr. Eric Hearle (officer in charge, 1928-1934), Mr. G. Allen Mail (officer in charge, 1937-1943), and various assistants, especially the late Mr.

Observations on the movement of fluids in the vicinity of the mouthparts of actively feeding female Dermacentor andersoni were made with the aid of trans-illuminated live-hamster pouch host-tissue. Following tick attachment and the invasion of ‘attaching cement’ into the outer skin layers, there appeared a progressive release of host blood as the tick settled into a feeding pattern. Short periods of sucking, each followed by an immediate ejaculation of saliva, became lengthened as feeding progressed, as did the resting intervals between sucking. Other movements brought about by the tick included a ‘toying’ of the tissue fluid, a rapid vibration of the same, and a distinct regurgitation of host-blood material. A sudden haemorrhage usually appeared at the feeding site about 2½ h after attachment of partially fed ticks.Speculations are made concerning the part played by the release of tick saliva and tick water loss, its probable relationship to host paralysis, and its apparent role in tick nourishment.

GREGSON, J. D. 1971. Studies on two populations of Ixodes kingi Bishopp (Ixodidae). Can. J. Zool. 49: 591-597.Studies on tick size, distribution, and hosts are made of two populations of fxodes kilrgi Bishopp, the individuals of which appear to differ only in size. I n Canada Iarge specimens were collected only in Alberta and mainly from carnivores and ground squirrels, while small specimens were found only in British Columbia and mostly on pocket gophers ant1 mice but occasionally on weasels. A study of available United States material revealed a similar pattern, the two populations being separated by the Rocky Mountains and the Wasatch Range, but each containing a scattered few speclniens o f intermediate size.It was shown that individuals of the two populations will interbreed and yield viable FT larvae. It if suggested that the species is in a state of evolutionary divergence northwards.

Tick paralysis continues to be one of the most baffling and fascinating tickborne diseases in Canada. It was first reported in this country by Todd in 1912. Since then about 250 human cases, including 28 deaths, have been recorded from British Columbia. Outbreaks in cattle have affected up to 400 animals at a time, with losses in a herd as high as 65 head. Although the disease is most common in the Pacific northwest, where it is caused by the Rocky Mountain wood tick, Dermacentor andersoni Stiles, it has lately been reported as far south as Florida and has been produced by Dermacentor variabilis Say, Amblyomma maculatum Koch, and A. americanum (L.) (Gregson, 1953). The symptoms include a gradual ascending symmetrical flaccid paralysis. Apparently only man, sheep, cattle, dogs, and buffalo (one known instance) are susceptible, but even these may not necessarily be paralysed.

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