Biology of 1. ricinm 303 



ecdysis at each stage. It is quite clear that the time required may be 

 very much prolonged under unfavourable conditions, and it is probable 

 that in nature it is not infrequently prolonged to two and even three 

 years. It should be noted that after very prolonged fasting we have 

 frequently found various species of ticks too feeble to feed upon a host. 



Influence of Season and Local Conditions, etc. 



According to Kossel, Schiitz, Weber and Miessner (1903, p. 39), 

 ricinus, in Germany, occurs chiefly on damp water-logged land with 

 rank vegetation comprised of long grass and bushes. Larvae and 

 nymphs are found in large numbers on cattle, especially in May and 

 June ; few ticks in these stages are found on cattle at other seasons. 

 The nymphs are the more commonly found throughout the year, and 

 are more prone to attack man than the other stages. In the spring 

 the larvae are encountered in masses on the ends of grass or twigs upon 

 which they have climbed from the ground where the eggs were deposited 

 by the female. Larvae, nymphs and females tnay be captured in a free 

 state at the end of April, proving that all stages may hibernate. They 

 are readily captured by dragging a woollen cloth over infested grass and 

 bushes. Samson (1909, p. 185) netted all stages from high grass along 

 paths in damp woods about Berlin in the spring of the year. Kossel 

 and his colleagues state that they are readily captured in the woods 

 during the spring to autumn ; they are so numerous in some localities 

 that when the cows return from pasture in the evening the farmers 

 collect the ticks by the litre and feed them to chickens. 



Copulation. 



A survey of the literature shows that the process of copulation (or 

 what I shall by preference term coupling 1 ) in /. ricinus was observed 

 at a very early date. De Geer (1778, p. 104) was the first to describe 

 and figure the sexes coupled. In de Geer's figure the male is shown 

 fixed with its venter upon the venter of the female, with its palps widely 

 separated, and its chelicerae and hypostome deeply implanted in the 

 female genital orifice, or vulva. Miiller (1817, p. 278) also observed 

 coupling in captive specimens, and stated that the sexes might remain 

 thus united for a week. Gene (1844, p. 771) observed coupling during 



1 The introduction of the <f mouthparts into the vulva, hereinafter described, con- 

 stitutes only a stage in the process of copulation ; see pp. 318 et teq. 



