glee oD hs. Tore dearth | wie Solas "ati ei 
Pe ee imac ba ea RPE CEE, BO eth pt, me Sse eee ee phe FE, 
EIS PO 25 na A E U g 
1878. | On the Ti si ia a of the Red Mites. 143 
to or very little beyond its tip; alga by a sunken polished plate at 
the end of the body dorsally; the plate but sparsely covered with 
hairs, elongate, square in front and broadening behind. The legs 
have the terminal hooks very short and blunt, the front pair is 
longest, the second shortest. Hairs of body barbed, slightly 
curved and attenuated. The scissor-like mandibles are faintly 
toothed within. With age the color intensifies to scarlet, but 
the legs, palpi and ventral surface are always more pale and sil- 
very than the superior part of the body. The male is smaller than 
the female, has more intense color, relatively somewhat longer 
legs, wih the body more pointed behind and more deeply con- 
stricted; the anal plate more narrow; ventrally his body is more 
distinctly constricted toward tip, and more deeply impressed 
longitudinally; also with the genital impression more distinct. 
His body becomes more creased and impressed with age, while 
that of the female becomes broader and more smooth and swollen. 
Average length of female when full grown about 3 mm.; male 
about 2 mm 
Widespread. We have it from Manitoba, Texas, various 
eastern States and from California. 
In each of the two egg-masses we have examined, the number 
ranged between 300 and 400, the mass being irregularly globose, 
and the eggs but loosely adhering to each other. We have not 
been able to ascertain the exact length of time required for the 
full development of the larva after attachment, but it is brief and 
seldom exceeds a fortnight, while the final transformation after 
detachment occupies but three or four days. Though the motion 
of the swollen and detached larva is slow, the legs move about 
with considerable rapidity, yet in the gradual change to pupa 
they shrink and are partially drawn in. Since De Geer’s time it 
has been known that some of the octopod mites are hexapods in 
their early life, and there can be no doubt but that all the Zrom 
bidide have hexapod larve. In addition to the locust mite above 
described, we have found another larval form attacking the mature 
C. spretus. Jt isat once distinguished from the larva of docustarum 
by the more prominent head, by the longer, more slender legs 
which are 7-jointed, the joints increasing in length to the penul- 
_ timate which is longest, and by the hairs, whether on the body, 
legs or palpi, being long, tapering and barbed. It is possibly the 
: larva of a large species which we have called Trombidium gigan- 
~ teum, distinguished by the following characters: 
Trombidium giganteum Riley—Adult 8 mm. to 9 mm. long 
pyriform, : somewhat flattened; no pronounced constrictions, but 
