TROMBIDIDAE OF MINNESOTA 131 
flamed, and many birds were so weakened as to become victims of 
dysentery and died. The mites did not bury themselves in the skin, 
but inserted the mouth parts and filled with blood. Some were seen 
fully engorged and walking away or dropping to the soil. When at- 
tacking men they do not seem to bury themselves in the skin, and the 
results of their bites are not so severe or extensive as usually described, 
but are similar to those of poisonous insects. The small area of in- 
flammation lasts for only a few days unless scratched or otherwise irri- 
tated and then disappears. Individuals, however, differ in their sus- 
ceptibility to these mites. 
Description of larva: Nearly circular in outline, color scarlet; 
size 0.25 by 0.17 mm. Dorsal surface with numerous long, stout barbed 
hairs; a trapezoidal shield at the anterior end, about twice as wide as 
long, and bearing four pairs of barbed hairs; paired eyes just laterad 
of the shield. The heavy capitulum is well exposed from above, widely 
petagonal in outline with the point forward, the mandibles protrud- 
ing beyond it; a wide, shallow median groove extending its entire length. 
Ventral side with numerous barbed. hairs, coxae close together, stig- 
mata between coxae I and II, anus about half way between coxae III 
and posterior margin of body. Mandibles enclosed in a more or less 
cylindrical sheath. Palpi stout and curved toward median line, borne 
at the lateral angle of the capitulum on the under side; segments II 
and III about as wide as long, segment IV nearly twice as wide as long, 
claw on segment IV long, stout and bifurcate, thumb stout and having 
several long plumose hairs on its tip. 
Legs stout with numerous barbed hairs. 
BIBLIOGRAPHY 
Banks, N. Some New American Acarina. Trans. Am. Ent. Soc. 21, pp. 
209-229 ; 1894. 
Banks, N. The Arcarina or Mites. Rept. No. 108, U. S. Dept. Agri., Office 
of Secy. 1915. 
Berlese, A. Trombidiidae—Redia—8, p. 291; 1912. 
Chittenden, F. H. Harvest Mites or Chiggers—U. S. Farmers’ Bul. No. 
671; 1915. 
Ewing, H. E. Syst. and Biol. Study of the Acarina of Hl. Bul. Univ. of 
TESZ, p: 1203 1909: 
Murray, A. Economic Entomology, Aptera, London, 1897. 
Osborn, H. and Underwood, L, M. Prelim. list of species of Acarina of N. 
Am.—Can. Ent., 18, pp. 4-12; 1886. 
Oudemans, A. C. Die bis jetzt bekannten larven von Thrombidiidae und 
Erythraeidae—Zool. Jahrbiicher, Suppl. 14, pp. 1-230; 1912. 
Riley and Johannsen. Handbook of M edical Entomology, p. 60; 1915. 
Riley, C. V. Report U. S. Ent. Com.; 1878. 
