424 
Biology of Ixodidae 
Observation 2. On 30. ix. 1913, 3 ^ and 3 $ were placed upon a ram’s scrotum. On 
1. X., they were all wandering about. On 2. x., 1 $ had attached herself. On 3. x., 
2 (J were attached. On 8. x., 1 $ was found partly gorged and 1 ^ was wandering 
about. On 9. x., the ^ and $ were found in copulation. 
Observation 3. On 14. x., 1913, 6 $ and 6 $ were placed upon a ram’s scrotum. On 15. x., 
a pair were found in copulation, the rest were attached in different places. On 17. x., 
aU the pairs were in copulation. 
Summary. 
Dermacentor reticulatus requires 3 hosts upon which to feed in the 
larval, nymphal and adult stages. All stages are readily reared on 
sheep. [Marzinowski and Bielitzer reared immature stages on rabbits 
and adidts on a horse.] Larvae and nymphs attached themselves 
quickly to the host 14-24 days after emergence; adults fed promptly 
after an interval of 44-58 days; doubtless they would have fed sooner 
if they had been tried. The tick feeds upon the ram for 3-6 days 
(mostly 4 days) as a larva, for 6-10 days (mostly 8 days) as a nymph, 
for 9-15 days as an adult (?). When adults of both sexes are placed 
upon the host they usually scatter and after the $ has fed for a time 
he seeks the $, copulation taking place iipon the host. There is evidence 
that the S tends to wander about, and this behaviour coupled with the 
observation, cited below, that $s are somewhat more numerous than 
ds, renders it probable that the latter may copulate with several 9s. 
The time required for metamorphosis was determined (at 30° C. only) 
as follows: it took 12-19 days before the larvae emerged from the egg, 
5 days for metamorphosis from larva to nymph and 12 days [17-18 
days in spring according to Marzinowski and Bielitzer] for metamorphosis 
from nymph to adult. Oviposition commenced, according to tempera¬ 
ture, 3-24 days after the gorged and fecundated female has abandoned 
the host, the process lasting 6-23 days, and during this period the 
female lays about 4000 eggs. Parthenogenesis has not been observed 
to occur. The loss of life observed in raising this tick under experi¬ 
mental conditions is less than is frequently observed in other species; 
thus, from a batch of 754 gorged larvae (many larvae and nymphs being 
preserved for our collection) we raised 247 nymphs which after engorge¬ 
ment, gave rise to 191 adults. These 191 adrdts were all descended 
from a single female (No. 1 in our protocol p. 423) and comprised 81 S 
and 110 9- The longevity of unfed larvae was not determined by us 
[they may survive unfed for 6 months according to Marzinowski and 
Bielitzer]; unfed nymphs survived for 37 days; we have seen a S survive 
for 474 days and a 9 for upwards of 450 days; the ticks at all stages 
