THE OATTLE GRUBS OR OX WARBLES 31 
The fifth-stage larva of H. bovis is slightly larger, but otherwise very similar 
in shape to that of H. lineatum. The armature arrangement is similar to that 
of H. lineatum, except ventrally, where only segments 2 to 9, inclusive, are 
armed; very rarely a specimen is found with armature on the tenth segment 
and with a single-or a few spines on the. anterior 
border only. In H. lineatum there is always a 
fairly broad band of spines on the posterior 
border. The posterior 
stigmal plates of dH. 
bovis are deeply exca- 
vated or funnel shaped 
toward the pseudostig- 
mal orifice. This ehar- 
acter is very reliable 
for distinguishing the 
species in this stage 
(fig. 18). 
THE PUPARIUM 
The puparium retains 
all the larval charac- 
ters, except that it as- 
sumes a different shape 
and darkens in color 
to almost black. Its 
dorsal side is nearly 
straight and flat, with 
the anterior end plain- 
ly showing the opercu- 
lum (fig. 16, d-f). The 
flat stigmal plates of 
H. lineatum and the wg, 13.—Hypoderma bovis: 
- funnel-shaped plates  Cephalopharyngeal skele- 
Fie. 12.—Hypoderma lineatum-: : . ton and mouth hooks of 
Cephalopharyngeal _ skeleton of H. bovis remain the Raiedestaee ipcual A, 
and mouth hooks of third- 
stage larva. A, spine; B, an- 
terior end, and D, posterior 
end of mouth hooks; C, tooth. 
Greatly enlarged (Laake) 
same as in the ma- 
ture larva and serve 
to distinguish the two 
species. 
spine; 8B, anterior end, 
and OC, posterior end, of 
mouth hooks. Se as 
(Laake) 
THE ADULT 
The adult of H. lineatum (fig. 19) measures from 12 to 13 millimeters in 
length and has a wing expanse of from 23 to 25 millimeters. The female 
with ovipositor fully extended measures 17 millimeters in length. The gen- 
eral color of the adult is black, banded with yellowish and orange hair. The 
shade of the colors *varies somewhat with different specimens and also 
changes according to the position and light in which the insect is viewed. 
The front, sides, and back of the head are covered with yellowish-white hairs. 
The thorax is vee 
clothed with 
yellowish hairs 
except  dorsal- 
ly, where the 
posterior part 
of the protho- 
Tax, ane the 
mesothorax are 
he reer ee, more ein y 
Biniee of ene age covered with 
arva. Greatly en- black and some 
larged (Laake) yellow hairs. 
On this area 
there are four distinct longitudinal lines which are nearly naked and shining. 
The basal segments of the abdomen are covered with grayish-yellow hairs, the 
middle segments are brownish black, and the terminal segments are clothed in 
orange-yellow hairs. The femora are black and the tibiz and tarsi brown. The 
entire legs are well covered with black and orange-colored hairs. The wings 
are Slightly fuscous and the veins are dark brown to black. 
: Posterior 
stigmal plates of fourth-stage larva. 
Greatly enlarged (Laake) 
Fie. 15.—Hypoderma bovis: 
