86 
Biologij of Ixodidae 
fi'om the nymphal skin they copulate with the gorged females which 
abandon the birds in the nest. The gorged nymphs from which the 
males issue are larger than those whence the females emerge. The 
time required for metamorphosis from egg to larva ranges between 84 
and 129 days at 12° C., the nymphs may emerge after 17 days or more, 
the females after 22 days and the males after 34-39 days. Larvae have 
survived unfed for over 163 days, unfed nymphs for over 260 days, 
males have lived up to 376 days and females up to 289 days; all stages 
during the periods stated being confined in corked tubes in a moist 
atmosphere at room temperature. Oviposition commenced 4-36 days 
after the gorged females were collected in the birds’ nests; about 
2.7 days would appear to be the usual period preceding oviposition. 
The female continues to lay for 6-39 days, during which period she lays 
a comparatively small number of eggs, viz. 2-30-380 as was to be 
expected according to the theory advanced by me regarding the Ixodes 
which are parasitic on hosts with relatively fixed habitatsk The female, 
after she has finished ovipositing, may survive for 0-41 days, she usually 
dies, however, within four days. 
The colouration in life and the changes in colour after death are 
different from anything hitherto observed in ticks, and it would be of 
interest to discover the reason for these colour changes. For notes on 
the variation in size, the process of copulation and the effect of the bite 
on man the reader is referred to the preceding pages. 
IXODES CANISUGAk 
The following notes relate to two lots (N. 1303 and 1304) of this 
species: Lot (a) comprised four replete females, one in copida, collected 
by me in sandmartins’ nests at Boyton Hall Farm, Suffolk, 11. vil. 
1911; they were found together with numerous other adults, nymphs 
and larvae infesting the young birds, gorged ticks and males being 
found within the nests. Lot (h) comprised 26 replete females and 
24 males, collected by Mr R. F. L. Burton from sandmartins’ nests at 
Longner Hall, Shrewsbury, 29. vil. 1911 ; these ticks reached Cambridge 
the day following. The females of both lots were isolated in corked 
tubes containing slightly dampened filter paper, the tubed ticks being 
maintained at room temperature in the laboratory. 
1 This Journal, iv. 46 (1911). 
2 The little that was hitherto known about the biology of this species is recorded in 
Ticlis, Part II. pp. 316-317, wherein Wheler’s observations are quoted. 
