PSOROPHORA COLUMBIA. 593 



the anterior segments shorter; lateral hairs of first two segments multiple, 

 double on third to fifth, single on sixth ; long single subdorsal hairs on third to 

 fifth segments. Tracheal tubes broad, band-shaped, irregularly flexuous pos- 

 teriorly. Air-tube large, strongly inflated, tapered on outer half, three times as 

 long as wide ; pecten of four teeth scattered over basal half of tube ; single tooth 

 a long blunt spine with a simple furcation towards base; a small tuft at outer 

 third of tube. Lateral comb of eighth segment of six scales joined by a basal 

 chitinous band ; single scale rectangular, twice as long as wide, with a long 

 terminal spine longer than the body of the scale, a stout, curved subapical spine 

 and three smaller ones on the sides. Anal segment longer than wide, ringed by 

 the plate ; dorsal tuft a long hair and brush on each side ; a small lateral tuft ; 

 ventral brush well developed, extending along the ventral line to base. Anal 

 gills long, twice as long as the segment, regularly tapered to a sharp tip, each 

 with a slight central trachea. 



Pupa (plate 149, fig. 706). Thoracic mass subpyriform, small tufts on an- 

 terior edge of mesothorax; air-tubes short, funnel shaped, obliquely truncate 

 at tip; crest of thorax rugose. Abdomen stout, rather short, hairs well de- 

 veloped; a pair of fan-shaped tufts on posterior margin of mesothorax and 

 another on first abdominal segment; long hairs on fourth and fifth segments; 

 three little lateral tufts on seventh segment and one on eighth. Anal paddles 

 with a distinct apical spine. 



Egg (plate 146, fig. 672). Eather large, fusiform, black, reticulated, covered 

 with recumbent spines, one of which arises from the edge of each cell-area. 



The eggs are laid on the ground, probably when dry, but in places where 

 water is likely to accumulate. The eggs apparently do not hatch until the 

 following year. They hatch immediately after a heavy rain, and the larvae 

 develop rapidly. Mr. Herrick has published observations on the life history. 

 He notes that the larvae appeared in a pool witTiin twelve hours after a rain. 

 They are found in all sorts of ground puddles, but principally in open ones, 

 often without vegetation and muddy. They abound in ditches along roads or 

 railroads, where these are not well graded, especially soon after such places have 

 been made and before they are filled with vegetation. We have not observed the 

 female attacking man in the vicinity of Washington, although the species is 

 common at times. Some of our specimens are filled with blood, but this may be 

 blood of animals other than man. Certainly the species is not a noxious one. 

 Thibault, who has observed the species in Arkansas, makes the following state- 

 ment : " Quite abundant and annoying near breeding-places. Prefers open 

 fields and large open marshes to woods ; often about dwellings ; will bite either 

 at midday or perhaps more frequently in evening; very troublesome to live 

 stock ; seldom taken indoors. Taken as early as May, but is not abundant until 

 summer as a rule. Seldom taken in fall. Females taken more often than 

 males." Hibernation occurs in the egg-state. We have no observations about 

 the mating habits. 



Eastern United States from New York southward. 



Cold Spring Harbor, New York, July 17, 1901 (F. E. Lutz) ; Delair, New 

 Jersey, July 10, 1901 (W. P. Seal) ; Kanawha Station, West Virginia, July 20, 

 1907 (A. D. Hopkins) ; Hyattsville, Maryland, August, 1906 (A. Busck) ; 

 Washington, District of Columbia (W. V. Warner); Woodstock, Virginia, 

 June 6, 1900 (F. C. Pratt) ; Grassymead, Virginia, June 21 (H. G. Dyar) ; 

 Arlington, Virginia, June 25, 1906 (A. Busck) ; St. Elmo and Del Eay, Vir- 

 ginia, June 7, 1903 (F. C. Pratt) ; St. Louis, Missouri, May 23, 1904 (A. 

 Busck) ; Atlanta, Georgia, July 4, 1906 (W. B. Summerall) ; Greensboro, North 

 Carolina, August, 1901 (F. C. Pratt) ; Rives, Tennessee, July 27, 1904 (H. S. 

 Barber) ; Corbin, Kentucky, August 24, 1904 (H. S. Barber) ; Little Rock, 



