[HEWITT] CANADIAN TICKS 233 



June.^ The larvae began to emerge in July. Bishopp and Wood (I.e.) 

 found the pre-oviposition period ranged from 7 to 134 days, the 

 incubation period from 33 to 71 days and the longevity of the larvae 

 from 50 to at least 346 days. The combined periods from the dropping 

 off from the host of the engorged females to the death of the last larva, 

 or the whole non-parasitic period, ranges normally from 159 to at 

 least 479 days. The larvae attach themselves to their host during 

 the autumn, winter and spring months. 



Dermacentor variabilis Say 

 Localities. 



Banks (1908) states "specimens come from many places in the 

 Eastern United States, from Labrador to Florida and Texas." 



Hadwen (1912) received specimens from Aweme, Man. (Coll. 

 N. Criddle, 2-VI-1910). 



Hosts. 



Hadwen (I.e. and 1913) records its occurrence on the following 

 hosts : 



Dog, cattle, horses, man. 



Banks (I.e.) states that it has been taken from a great variety 

 of animals including man, but that it seems to prefer dogs and cattle 

 to smaller animals, which he suggests is due to the fact that the 

 freshly moulted individuals climb up several feet from the ground 

 in wait for a host. 



Seasonal History and Life Cycle. 



From 1910 to 1912 Hadwen (1912 and 1913) attempted to rear 

 this species through its various stages on tame rabbits and succeeded 

 in 1911 and 1912. In Manitoba most of the engorged females were 

 collected in June; the earliest specimen was captured (by Mr. Norman 

 Criddle at Aweme, -Man.) on May 25th and the latest on July 17th. 

 As soon as the warm weather follows the disappearance of the snow 

 the adults are found everywhere and are very annoying to man and 

 beast. As in the case of D. albipictus and D. venus tus the partly 

 engorged females are remarkably tenacious of life in comparison with 

 the fully gorged and ungorged females. 



^Misfortune constantly attended my life-history experiments, on this species 

 and D. venustiis. In the summer of 1910 detailed notes of the life-history studies 

 of D. albipictus were lost during my absence, having apparently been swept off my 

 table into a waste-paper basket; perhaps fate was a more able judge than I of their 

 worth! When similar studies were being made in 1912 of D. venustus the carelessness 

 of an unknown person caused the wholesale escape of ticks in my room and neces- 

 sitated the closing down of the experiment. 



