Evening star. [volume] (Washington, D.C.) 1854-1972, 1928-07-08
Chiggers Arrive Somewhat Late

! clothing is tight; If so, many may hold
| on
AS they pass upward many of the
| larvae either stop themselves or are
stopped at the carriers Gf any,, II these
are worn below the knees. II they pass
the garters large numbers will attach
in the space under the knees. Those
| that get by the knees usually go as lar
as the waistline.
Two factors are of importance in re-
gard to the localization of chigger at
| tachment-the tightness of the clothing
at certain parts of the body and the
thickness of the skin. The present
mode in women's clothing fashions
gives q wider range to the wandering
chigger Carriers around the legs and
belt around the waist act as semi
effective barriers.
| For a great many minutes, sometimes
| for a few hours, the larvae run over
the skin, hunting favorable place at
which to stake claim. These rapidly
moving larvae are halted by the garter
| Cor good "roll') or belt pressure, and,
after struggling some time, either to
pass through the mesh of the clothing
| at these points or to extricate them
selves, may settle down without further
search.
DR.. Ewing has watched these active
larvae on his skin and that of others,
before and after attachment, and finds
! that tight clothing does not aid them
| in digging in" as has been so fire.
quently supposed. They hold on ex-
| ternally as a tick does,
The thickness of the skin is of great
! Importance In localizing chigger attach
ments. Where the skin is unusually
tough the larvae make punctures with
great difficulty, or not at all. and OF
| those that do stick many cannot hold
on during the body movements OF the
| host or are not able to reach the lymph
supply of the true skin OF the thou
sands of busy chiggers observed by Dr.
| Ewing not q single one was found on
| the calloused parts OF the hands or
| feet.
| 1t was long the belief of entomologists
| that chiggers lived upon the juices OF
plants. When it was learned by actual
rearing experiments that several of the
species were normally parasitic on ter
| restrial tracheateS mot true insects, but
| things like spiders and centipedes) this
theory was dropped, and 1t was COM
monty assumed that the chigger larvae
were normally parasitic on tracheates
and closely related invertebrates.
This notion was equally shared by
| the mite specialist ana the general
entomologist; but that the chigger
larvae could be normally parasitic on
vertebrates was never suspected: in fact,
the references to their death feast" on
| man or domestic animals continued as
numerous as before.
When DR.. Ewing began, ten years
ago. his search for the natural host of
the species occurring in Virginia and
Maryland. he collected all insects found
parasitized with chigger larvae. These
| larvae were examined TO see II any Of
them belonged to the species attacking
man, or were, In fact, true chiggers.
Although many insects and other
ground dwellers were found parasitized.
in no instance did these parasitic larvae
prove to be the species attacking man.
Not satisfied with this method Of In
vestigation. another was instituted. DR..
Ewing collected hundreds Of insects
from vacant lots that had grown up In
blackherries. These he infinitely ex-
amined In his laboratory. and failed to
find one single specimen of the eastern
chigger.
Although never believing m the old