INSECT ENEMIES OF WESTEKN FORESTS Ql 



1)1). Caterpillars travelling with a loop- 

 ing motion ; with three pairs of 

 true legs in front and two or 

 three pairs of prolegs in the rear, 

 loopers or measuring worms, page 74. 

 cc. Olive-green caterpillars with black 

 and yellow stripes on top and 

 sides, brown or red heads ; feed- 

 ing on California oaks. 



California oak worm, page G8. 

 (2) Caterpillars very hairy. 



aa. Caterpillars brightly marked with 

 blue, red, or yellow spots and 

 long pencils or distinct tufts of 

 hairs like a toothbrush. 



tussock moths, page 69. 

 hh. Caterpillars of dull colors, black, 

 and yellow, feeding in masses on 

 terminal branches. 



tiger moths, page G6. 

 cc. Blackish caterpillars with row of 

 nearly square, white blotches 

 along the back, irregular white 

 marks along the sides, and brown 

 spines and hmger, paler hairs. 

 Feeding on poplar and willow. 



satin moth, page 72. 



2. Leaves chewed, but defoliated part of tree not covered with 



silken webbing. 

 a. Work done by caterpillars with scattered spines or 

 hairs; three pairs of front legs, four pairs of 

 median prolegs, and one pair of anal larvapods. 



(1) Yellowish-green or brown, leathery cater- 



pillars with short dark hairs and seven 

 or eight stout branched spines on nearly 

 every segment ; feeding on ponderosa pine. 



pandora moth, page 64. 



(2) Black caterpillars with fine, branched spines 



on each segment, middle row of spines 

 bright yellow ; feeding on species of 

 Ceanothus, 



California tortoise shell butterfly, page 165. 



(3) Large, stout caterpillars with sparse, stout 



tubercles ; feeding on broadleaved trees 



and shrubs giant silk moths. 



(4) Yellow and black caterpillars with branched 



spines ; feeding on willow, popular, and 

 other broadleaved trees and shrubs 



brown day moth. 

 6. Work done by naked slugs with three pairs of true 

 .legs and six to eight pairs of prolegs ; sometimes 

 covered with slime ; one end of body frequently 

 held in midair when disturbed sawflies, page 87. 



3. Leaves mined internally. 



a. Working inside of coniferous needles 



needle miners, page 85. 

 &. Working in broad leaves leaf miners, page 86. 



4. Leaves skeletonized, with midribs and veins still evident. 



a. Work on broadleaved trees done by active grubs 

 with three pairs of true legs, or by hard-shelled 

 beetles^ leaf beetles, page 92. 



B. Trees sickly, leaves not chewed but yellowing or covered with a sticky 



exudation or black smut sap-sucking insects, page 44. 



C. Leaves stunted, galled, or swollen gall makers, page 52. 



^ Similar work is done on broadleaved trees by a great variety of caterpillars, saw- 

 flies, etc., and to be certain of the insect responsible, specimens must be captured and 

 Identified. 



