Feb. '08] JOURXAL OF ECONOMIC ENTOMOLOGY 4$ 



host, but some species have been observed in copulation off the host. 

 In most of the species which pass their molts off the host (the genus 

 Ixodes possibly excepted) it seems to be necessary that the male at 

 least attach and take food before the sexual instinct is developed. In 

 Margaropus annulatus, which molts upon the host, the male detaches 

 as soon as the nymphal skin is shed and goes in search of the female, 

 which it embraces when found and with which it remains in copulation 

 until the replete female drops. The Brown Dog Tick, a species of 

 Rhipicephalus, has similar habits, females often being found each with 

 several males attempting to embrace them. Apparently Dermacentor 

 nitens also has the same habit of remaining in copulation on the host. 

 "While the two sexes are usually nearly equal in numbers, yet by the 

 dropping of the female and remaining of the male on the host, the 

 latter are usually found present on the host in greater numbers. 

 Lounsbury has made extensive observations upon the mating of Am- 

 hlyomma hehmeum, the habits of which species are very remarkable. 

 He has found that the female goes in search of the male, the latter 

 accepting the female only after having attached and fed for several 

 days. Considerable difficulty has been experienced by the writer in 

 getting the sexes of the three species of Amblyomma and Dermacentor 

 variabilis to copulate, and there remains much to be learned in relation 

 to this habit. Mr. J. D. Mitchell has observed Amblyomma amer- 

 icanum apparently in copulation on shrubbery. Wheler mentions 

 observing Ixodes ricinus as apparently in copulation off the host; 

 this act he describes as taking place through the introduction of the 

 mouth parts of the male into the genital pore of the female. The 

 writer has observed this same habit in Ixodes scapularis, both upon 

 and off the host. An unengorged, unattached female taken in the 

 field from a hunting dog and placed in a pill box with unattached 

 males taken from the same dog was shortly after found in copulation 

 with one of the males. From this it would appear that it is unneces- 

 sary, for the female of this species at least, to take food prior to fertili- 

 zation. The habit of fertilization through the introduction of the male 

 mouth parts into the genital opening of the female thus appears to 

 be typical of the genus Ixodes. 



Geographical Distribution. — While ticks are found which have 

 adapted themselves to colder climates, it is in the tropics that they are 

 found in the greatest numbers. That the distribution of species is 

 controlled by cold is well illustrated by the original quarantine line 

 against the cattle tick in this country. Humidity and precipitation 

 also appear to be factors in control of the distribution, as in the case 

 of the Gulf Coast Tick, Amhlyomma maculatum, a species found in the 

 immediate vicinity of the Gulf Coast from Cameron Parish, Louisiana, 

 to the Rio Grande Eiver in Texas. 



