97 
Fig. 21. — Clover Hay-worm. Hypsopygia costalis, larva. 
Greatly enlarged. 
Osboni mentions Pyralis farinalis, as well as H. costalis, as injur- 
ing stored clover hay in Iowa. 
Stages. — ^The full-grown caterpillar (Fig. 21) is three quarters of 
an inch long, and dull brown with an olive tinge usually, tho some of 
the largest larvae re- 
tain the pale color of 
the young larvae. The 
head, shield, and cau- 
dal plate do not turn 
dark until after the 
last moult, according 
to Riley. The thorac- 
ic segments are much 
wrinkled, and most 
of the remaining seg- 
ments are each di- 
vided by a transverse 
groove into two subsegments, the anterior of which is the larger. On 
each segment are several smooth shining areas, each bearing a fine 
white hair. 
The cocoon is half an inch in length, oblong-oval, and composed 
of white silk, intermingled with excrement and bits of hay. 
The chrysalis, as described by Riley, is honey-yellow, with the 
segments and members clearly defined by the darker color of the "in- 
sections." 
The moth (Fig. 22) is small — the largest specimens spreading 22 
mm. — and has silky wings tinged with purplish above, margined with 
orange, and fringed with golden yel- 
low. On each of the upper wings are 
two large golden spots so situated as 
to divide the front margin of the wing 
into thirds ; each of these spots con- 
tinues backward to the hind margin 
of the wing as a narrow lilac line. On 
each hind wing are two wavy trans- 
verse straw-colored lines, one across 
the middle of the wing, and the other 
half-way between the first line and the 
base of the wing. Underneath, the 
wings are pale yellowish with the markings indistinct. Head and legs 
straw-colored ; antennae and palpi pale orange, tinged with lilaceous. 
Life History and Habits. — In Missouri and Ohio there are two 
generations a year and apparently more or less of a third brood. In 
winter, larvae of all sizes are to be found in clover hay. In Ohio, Web- 
ster found pupae no earlier than May 25; moths emerged June 12 and 
laid eggs June 13 to 17, other moths issuing from June 3 to July 15; 
young larvae (very small to half grown) occurred July 1 ; larvae and 
pupae were seen August 6 ; and adults of the second generation began 
^^^^^ l^^^^iRW* -iwi. 
Fig. 22. — Clover Hay-worm, 
Hypsopygia costalis, moth. 
Twic€ natural width. 
