166 
IOWA ACADEMY OF SCIENCE Voi, XXIX, 1922 
The larva is a beautiful slender hairy caterpillar about one 
and one-fourth inches long when fully grown. The dominating 
color is bright canary yellow. Four dense cream colored tufts 
of erect hairs on the first four abdominal segments are character- 
istic and give a basis for the name. A dorsal and a lateral stripe 
of blackish, two long black hair pencils projecting from the coral 
head and another from the posterior end and two brilliant red 
protuberances on the sixth and seventh abdominal segments lend 
to the decorations. The larva when dropping from one object 
to another spins a fine web which it can reclimb. The adult 
male is an ashy gray moth expanding about one and one- fourth 
inches. The female is light gray and is wingless, which fact 
offers opportunity for control measures. The body is about three- 
fourths of an inch long and heavy. The pupa surrounded by 
a hairy cocoon is attached to a tree twig, under loose pieces of 
bark on fences or on buildings. When placed on a twig, as is 
most frequent, it is usually wound in one or more leaves. The 
wingless female upon emerging clings to the cocoon and after 
mating deposits ' her eggs on one side of the cocoon and covers 
them with a white frothy coating in which stage the eggs of the 
second brood pass the winter. The spherical eggs are smooth 
except that they are covered with a lintlike mass. The color is 
a tawny cream. The largest diameter is slightly less than one 
millimeter. The eggs are almost always laid on the cocoon as 
already stated. 
Numerous winter egg masses were collected and the eggs con- 
tained on fifty representative cocoons were carefully counted. 
The results were as follows: 
332 
382 
540 
481 
667 
469 
472 
500 
237 
415 
406 
461 
456 
302 
466 
516 
579 
454 
559 
422 
569 
674 
362 
460 
449 
534 
460 
526 
278 
507 
568 
402 
548 
527 
506 
602 
567 
688 
303 
341 
700 
438 
410 
708 
335 
504 
378 
328 
491 
573 
The smallest number is seen to be 237 and the largest 708. The 
total number of eggs laid by the fifty moths was 23,812, making an 
average of 477.44. 
The eggs that were collected and kept indoors began hatching 
the 7th of April. A large number of adults was thus reared 
under observation. A definite record was kept on the time of 
