Illinois Natural History Survey -2- Identification Notes 3 
Coxa s the first segment of each leg, that is, the 
segment which attaches the leg to the body. 
The coxae often bear spurs, figs. 2 and 3. 

Key to Illinois Ticks of Economic Importance 
(Larvae, which have only three pairs 
of legs, are not included, 
1. Body leathery and warty; mouth parts attached to the undersurface 
of the tick oeseeoepeoeceoeageseeeneeeeeoeeeseeoen Family ARGASIDAE, 2 
Body hard, finely wrinkled but not warty; mouth parts attached to 
the front margin of the tick cessceeseoees Family IXODIDAE, 3 
2e Upper and lower surfaces of body separated along the sides by a 
fine, continuous, sunken line; front margin of the tick evenly 
rounded secseovaececoveese adults and nymphs of Argas persicus 
Upper and lower surfaces of body not separated along the sides 
by a fine continuous, sunken line; front margin of the tick 
with a distinct, NOGH—LAKG ORUCNCLON cecuseeenvesesessdseceens 
cesccccccsececccesses adults and nymphs of Qrnithodoros kelleyi 
3e Fore coxa with two large, equally long, closely joined spurs, fig. 
2 @eoeoeseeCGeaese eoaneeseaeeosceesCneoeoeeeseeeeeaseeeeseoeoeesoaaeeoeotnoeoe 
Fore coxa with or without spurs, if with spurs these are widely 
spaced and, at the most, only one of them is long, fig. 3 ese 6 
4. Body without any silver-colored markings; base of capitulum (BC) 
hexagonal in outline, similar to figs 4 seecesereascccvesvevece 
Delage oweeteuehcevveseess ses eeeUULus of Rhipicephalus sanguineus 
Body with silver-colored streaks either near the front part of 
the tick or over the entire upper surface; base of capitulum 
(BC) rectangular in outline, figs 1 ccescecccscsevcccccssvees 
5- Found feeding in fall and winter on large domestic or wild animals, 
not on man or dogs secseeees adults of Dermacentor albipictis 
Found feeding in spring and summer on large and small animals, 
frequently on man and dogs .. adults of Dermacentor variabilis 

6, Palpi short, segments II and IIt(PII & PIII) each ringed by a 
sharply protruding ridge, fig. 4 SCORSHSHHASSEHOROALOHO ED OOH EEHED 
tepeecseaceedesersen adults iand nymphs of Boophilus annulatus 
Palpi generally longer, segments II and III both not ringed by a 
prominent ridge SCOOT HOESHEHHOEHEHDHPSSCHEHHOHHOESTOOCHEHOCEHOLHR EOS 
