THE CALIFORNIA PHRYGANIDIAN (PHRYGANIDIA 

 CALIFORNICA PACK.) 



BY VERNON L. KELLOGG AND F. J. JACK. 



(With Plate Ivi.) 



Last fall and this spring the oak trees, especially the 

 live-oaks ( ^nercus agrifolia), in the vicinity of the Le- 

 land Stanford Jr. University and of Palo Alto suffered 

 serious defoliation by the attacks of the larva of Phryga- 

 nidia californica. The pest is not remembered to have 

 been so abundant here before. The caterpillars appeared 

 in astounding numbers, the continuous dropping of frass 

 from the infested trees attracting common attention. The 

 caterpillars were conspicuous, also, on the tree trunks 

 and on fences and the v^alls of buildings near trees, often 

 massing in a way suggesting the well-known Datana 

 masses, although never forming such compact and iso- 

 lated bunches. The special interest attaching to this in- 

 sect, because of its systematic isolation among the Heter- 

 ocera, its limited geographical range, and its capacity, 

 abundantly shown last fall and this spring, for damage, 

 led us to make the observations recorded in the following- 

 notes . 



The larv«, mostly full-grown, were noticed in great 

 numbers on September 19, 1894. They were feeding 

 singly, although crowded together by numerical abun- 

 dance. The massing already referred to was especially 

 noticeable in the crotches of the trees and on the trunks 

 and large branches. The larvae in these groups main- 

 tained an irregular jerking of the head, much less pro- 

 nounced than the jerking of Datana larvae but very like 

 it. The caudal extremity of the body is commonly ele- 

 vated when the larva is at rest, although the anal feet are 

 used when the caterpillar is walking. 



A few chysalids were seen on September 19. By Oc- 



2d Ser., Vol. V. September 10, 1895. 



