92 



coming- into immediate contact with the ground, in one way or 

 another. The cayor worm, in animals, shows a marked prefer- 

 ence for the skin of the scrotum. In man, on the contrary, the fly 

 lays its eggs on clothes, etc., impregnated by perspiration. 



Specimens of Auclimeromyia (Cordylohia) jnaegrandis, Aust., 

 were observed at Sankisia and Bukama. Bezzi considers that its 

 biology is analogous to that of .4. hiteola, but the fact that four 

 specimens were taken in urinals leads the authors to suppose that 

 the larvae of this species are nourished on decomposing organic 

 matter. 



[Eoubaud has recorded (see this Review, p. 69) that A. pme- 

 grandis is parasitic on the ant-bear (Orycterojms). — Ed.] 



Hadwen (Seymour). The Life-History of Dermacentor variabilis. 

 —Parasitology, v, no. 4, Jan. 1943, pp. 234-237. 



After attempts extending over a period of three years, Derma- 

 centor variabilis has been reared through its various stages on 

 tame rabbits. 



In Manitoba, as soon as the snow disappears and the warm 

 weather begins, adults are common everywhere and a great annoy- 

 ance to man and beast, but there is no record of larvae and 

 nymphs having been taken at this season, probably because no 

 systematic search has been made for them. Most of the gorged 

 females used in these experiments were obtained in June — the 

 earliest being on May 25th and the latest on July 47th — on man, 

 cattle, horses and dogs, these being the only known hosts for 

 Manitoba. 



Copulation has not been observed, but it probably takes place 

 on the host, as males and females are usually present in approxi- 

 mately equal numbers. Oviposition is similar to that of other 

 ticks. A very slightly gorged female removed from the host 

 will lay a few eggs and these partly gorged females, as in D. 

 albipictus and D. venustus, are far more tenacious of life than 

 fully gorged and ungorged females. At first the larvae do not 

 take kindly to the rabbit as a host, whilst on a fowl they became 

 very active but refused to remain on the bird. When not upon 

 a host the immature ticks require moisture. After the last moult 

 small whitish droplets exude from the bodies of the nymphs. In 

 the dry climate of Manitoba this secretion is probably a protec- 

 tion against desiccation. 



The conclusions are that D. variabilis is a three-host tick and 

 can be raised experimentally on the rabbit. Starting with an 

 adult female in the spring, it is very probable that the life-cycle 

 is carried as far as the nymphal moult during the summer and 

 autumn, and that the winter is passed in this state, the adults 

 emerging in the spring. Under laboratory conditions about 240 

 days are required for adults to issue, reckoned from the time 

 when the gorged mother tick abandoned the host, without taking 

 into account the variable period which the tick may have to wait 

 for a host when unfed. 



