122 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



166. The American lappet-moth. 

 Gaslropacha americana Harris. 

 Order Lepidoptera ; family Bombycid^. 

 The interesting larva of this moth rarely occurs on the oak. 



Larva. — Body broad, somewhat flattened ; the lateral ridge produced on each seg- 

 ment into a pair of hairy lappets, white, edged with gray, and fringed with long radi- 

 ating hairs. On the eighth abdominal segment is a round black hump ringed with 

 white. The body is white and gray, mottled so as to resemble the pale bark of the 

 ash or poplar. When creeping two transverse bright scarlet bands are disclosed in 

 the sutures just behind the second and third thoracic segments. On each segment 

 are two dorsal, curved spindle-shaped dark gray spots; the sides are clouded with 

 dark gray. Length 55-60™™. 



167. The Californian phhygaxidia. 

 Phriiganidia califorriica Pack. 

 Order Lepidoptera ; family Zyg^nid^. 

 Very destructive to young oaks, a naked, yellowish-white caterpillar, striped with 

 black and white, with a large head, wandering incessantly over the bushes and feed- 

 ing very rapidly ; spinning no cocoon, but the chrysalis, yellowish and black, attached 

 by the tail to fences, &c. 



This is, by its numbers and familiar habits, one of the best known 

 and most destructive insects of California. The following account has 

 been furnished me for Hayden's Report by Mr. Henry Edwards:* 



"This insect is also very destructive to our young oaks, the caterpillars, which are 

 naked perfectly and with the head almost monstrous in size, making their appearance 

 about the same time as those of CUsiocampa. They are 

 restless little creatures, wandering incessantly over the 

 trees and feeding very rapidly. They spin no cocoon, 

 but hang by the tail, like the larva of Vanessa, etc. The 

 change to the chrysalis is undergone in April antl May, 

 and the moths appear in about fifteen or sixteen days. 

 There is a second brood of these insects, the imagos of 

 Fig. 38.-Califoinian Phrygani- ^^^le latter appearing in September and October. IndeecJ, 

 dia. — From Packard, after j. ■, ■ xi • ji i ^i 



_, iresh specimens are now upon the wing, though the sec- 



ond brood is by no means so abundant as the first. I have 

 observed that Phryganidia and CUsiocampa never associate upon the same tree, and 

 I think that the former has always the mastery. This is perhaps owing to some ex- 

 cretion from its body which is uu pleasant to the CUsiocampa, but of course I do not 

 speak with certainty as to this fact. It is, however, sure that they are never found 

 in large quantities on the same tree. I am inclined to think that Phryganidia is more 

 destructive to the oaks than the other species, as it feeds solely upon Querctis, while 

 the other, as I have said, is not so particular in the choice of its food. I inclose my 

 published description of the eggs of Phryganidia." I quote Mr. Edwards's description 

 of the egg and larva : 



" The egg is spherical, a little flattened above, shining, yellowish- white at exclusion, 

 attached in clusters of about ten or twelve to the upper sides of the leaves. The 

 third day the apex of the egg assumes a dull orange hue, afterwards changing to a 

 bright reddish-purple and gradually to a duller shade as the young larvte emerge. 

 The eggs were laid by a female in my possession on July 5. In the young larva the 

 head is very large, almost monstrous, pale olive-brown, with a narrow black line at 

 base ; body pale canary-yellow, with four rows of black spots arranged longitudi- 

 nally in lines. 



* A. S. Packard, jr., Report on the Rocky Mountain Locust, dec. Hayden's Report 

 U. S. Geological Survey of the Territories for 1875. 



