THE CAYENNE TICK. 151 
NATURAL CONTROL. 
In order to determine the effect of water seven partially engorged 
females were submerged May 29, 1906, for 18 hours. After removal 
all became active and on May 30 were again submerged for 45 hours, ° 
only one surviving. As yet no parasites have been found to attack 
this tick. The natural enemies of the cattle tick, as described in 
Bulletin 72, undoubtedly destroy large numbers of this species. 
ARTIFICIAL CONTROL. 
Owing to the great longevity of the nymphs and adults, and to the 
many hosts which this species attacks, the rotation method of eradi- 
cation is impracticable. Frequent mopping or dipping with any of 
the standard tick dips must be resorted to. To be effective, mopping, 
dipping, or hand picking should be practiced often enough to destroy 
the females before they become engorged; that is, every 10 days. 
THE CAYENNE TICK 
Amblyomma cajennense (Fabricius). 
DESCRIPTIVE. 
The common name of this species is taken from the locality in 
which it was first collected and from which the specific name was 
taken; that is, Cayenne, Guiana. 
Adult (Pl. XII, figs. 2, 3, 5-7) —Males from 3 by 1.75 mm. to 
4 by 2.50 mm. Females, unengorged, 3.5 by 2 mm. to 4.25 by 2.5 
mm.; engorged, from 10 by 7 by 4 mm.to 12 by 8 by 6mm. Males 
pale yellow or brownish yellow, with irregular silvery white markings 
or streaks, and brown or reddish brown spots, all arranged to form a 
definite but complex pattern. Unengorged female yellowish; scutum 
largely silvery, with a brown line on each margin reaching back from 
the eyes. Engorged females dull bluish gray, with dark purplish 
brown reticulations. 
Nymph (Pl. XII, fig. 4)—Unengorged, 2 by 1.25 mm.; engorged, 
from 3.25 by 2 mm. to 4 by 2.75 mm.; length of capitulum 0.407 mm. 
(from tip of palpi to base of emargination of scutum); scutum 0.561 
mm. long by 0.786 mm. wide. Upon emerging the nymphs are of a 
dark-brown color; this soon turns to light brown, with intestinal 
markings showing through as dark-brown bands. As with amer- 
icanum, the sex of the nymph can be told a day or two prior to 
molting by the silvery markings which show through the to-be- 
molted skin. 
Larva (Pl. XII, fig. 1) —Unengorged, 0.65 by 0.51 mm., yellow- 
ish, the scutum marked on the lateral margins with dark red; engorged, 
2.5 by 2 mm., ovoid, bluish gray. Length of capitulum 0.195 mm. 
(from tip of palpi to base of emargination of scutum); scutum 0.248 
mm. long by 0.374 mm. wide. 
