LIFE HISTORY OF NORTH AMERICAN TIOKS. 45 
DEVELOPMENT OF THE ARGASIDA. 
The first of the two families of ticks, the Argaside, is represented 
in the United States by 2 genera and 6 described species. We have 
studied a representative of each of the genera.! 
All of the argasids so far as known, with one exception, pass their 
molts off the host. The larve of species belonging to the genus 
Argas that have been studied remain attached to the host for several 
days while engorging, but the nymphs and adults require only a 
few hours at most to engorge. The nymphs molt two or three times, 
following as many engorgements. The adults engorge repeatedly, 
each engorgement being followed by oviposition. Unlike other 
species of the genus thus far studied, Ornithodoros megnini engorges 
and passes the first molt upon the host; as a nymph it remains 
attached to the host for a long period, then drops, molts, is fertilized, 
and oviposits without engorging as an adult, shortly after the com- 
pletion of which it dies. So far as known it is the only species of 
tick that does not engorge in the adult stage. Two species of Orni- 
thodoros (savignyt and moubata) are known to pass the larval molt 
before feeding, the latter molting the larval skin while still in the egg. 
The periods of oviposition, incubation, and molting vary with the 
temperature; for this reason temperature records have been in- 
cluded in the tables. With the exception of Ornithodoros megnini, 
the females of the species known engorge and oviposit repeatedly. 
The longevity of some of the species, particularly those of the genus 
Argas, is quite remarkable, as is shown in the following table: 
TasLeE III.—Marimum longevity recorded for ticks of the family Argasidz. 
Maximum longevity of stages.2 
Species. Nymph, | Nymph, 
Larva first second | Adult. 
stage stage. 
Days. Days. Day Days. 
LASHES AS TOTO 0 RISE Aaa ner Os ee Rr ee a amines re 164 269 445 880 
OnmLhodoros miepninit ss 2350565 We CE eee ee ee SO sce e Sees [Rerorgea 8 638-++ 
Genus ARGAS Latreille. 
Six well-established and 4 doubtful species are included in the 
genus Argas by Nuttall and Warburton in their monograph of the 
Argaside, miniatus being placed as a synonym of persicus. In 
addition to miniatus, which we have studied, only one other species, 
brevipes, is known to occur in the United States, although Argas 
reflecus has been erroneously reported as occurring here. Several 
of the species, particularly miniatus and reflexus, are the source of 
1 Two other species of Ornithodoros (0. talaje and O. turicata) -re being studied. 
2 Longevity of third nymphal stage of A. miniatus not determined. 
