146 INSECTS AFFECTING DOMESTIC ANIMALS. 
may be an error. Of the females, however, it is certain that they bury 
themselves in the skin of their victims. From the first they hold on 
with such tenacity that no ordinary brushing will remove them. It 
seems to be at this stage in their existence that impregnation takes 
place. The males now are often seen in copula with them, and so 
remain apparently for days, or until the tumefaction of the skin excited 
by the embedded female closes around her so as to shove him off. Here 
ends about all actually known of this history. From analogy we may 
infer that the period of gestation being completed, the gravid female 
lays her eggs in this well-prepared nidus, or, more particularly, that | 
they remain and are hatched in her distended stomach, after which 
they crawl out and drop to the 
ground. If in a dry, shady 
spot, they undergo transforma- 
tion to the perfect form; if ina 
wet spot or in the sun, they 
perish. 
“Upon man I have never 
heard of the process continuing 
to theend. The itching caused 
by it generally attracts atten- 
tion sufficiently to have the in- 
‘truder hunted out. With the 
lower animals it is different, 
Fic. 77.—Sarcopsylla gallinacea: female—enlarged ani pl oy BI Lk 
puis Gindcer Life, drawn by Packard): : 3 Spots bare of feathers, or near- 
ly so, are selected in preference. 
A small knot resembling a wart grows over the insect, and so numerous 
and large at times as to spread over the eyes and into the jaws, and, 
blind and famished, the victim dies. In cases not fatal, after a month 
or two these knots or warts drop off, leaving a scar resembling a burn. 
With very young chickens or puppies death generally comes in the 
first stage, when every portion of their bodies is covered with innumer- 
able enemies.” 
While some portions of this account would seem to refer to the chigoe 
or Sarcopsylla penetrans, especially that portion referring to the attacks 
upon man and other mammals, it no doubt includes about all that is 
known regarding the actions of this pest, and no one, probably, is better 
acquainted with the habits of the insect. There is also opportunity 
for confusion with the work of some of the Sarcoptes infesting fowls 
in cases where the observer cited was unable to make personal investi- 
gations. 
OpossuM FLEA. 
(Pulex simulans Baker.) 
This species, described from the opossum, is said to be closely related 
to irritans and distinguished from it by the mandibles and hypopharynx 
being very short, not reaching one-half the length of the anterior coxe, » 
