324 



PSYCHE. 



[ Septetnbei 1S92. 



Mature larva. — Very variable in color. 

 The head is as in H. ahii described above, 

 the color of the body varies much in the 

 amount of black from entirely black to nearly 

 all yellowish. The hair is like that of 

 H. ahii in structure and the white pencils are 

 the same or partly yellowish, but the hairs 

 that arise from the warts and obscure the 

 body are nearly maize yellow* and the 

 amount of black at the ends of the body is 

 variable. Besides there is usually present 

 the series of lozenge-shaped black dorsal 

 tufts on joints 5-12 winch is seen on H. mac- 

 ulata; but these may be much reduced, or 

 absent. I have not, however, seen any ex- 

 amples in which they were wanting which 

 also had the black extremities well devel- 

 oped. One example occurred to me with its 

 hair entirely yellow except the white pen- 

 cils. From this there are all intergrades to 

 a form with joints 2-6 and 10-13 bearing deep 

 black hairs besides the black dorsal tufts on 

 joints 7-9 and the usual white pencils. Ex- 

 amples occur that are not to be distinguished 

 from H. maculata, that is with only the 

 eight dorsal tufts colored black. A singular 

 variety was found with joints 4-5 and 10 pos- 

 teriorly to 12 and the dorsal tufts on joints 

 6-10 black, joints 2, 3. 12 laterally. 13 and all 

 the hair from warts 3-6 on joints 6-10 white, 

 the hair from warts 1-2 on joints 6-10 yellow. 

 White pencils normal. 



Food plants. — Willow (Salix) and alder 

 (Alnus). 



Habitat. — California, in low land near the 

 coast. (Santa Barbara and San Francisco). 



Orgyia leucostigma Smith and Abbot. 



1797 — S. and A., Lep. ins. Ga., 157, pi. 79. 



18S9— Hy. Edw., Bull. no. 35, U. S. N. M.. 

 p. 63 (gives 23 references). 



1889 — Packard, 5th rept. U. S. ent. com., 

 p. 262. 



In spite of the fact that the larva of this 

 species has long been known and excellently 

 illustrated and described by Dr. Riley, I 



* Ridgway's Nomenclature of colors, PI. vi. fig. 21. 



have seen no account of the preparatory 

 stages that agrees with my observations. Dr. 

 Riley says :— "Six days after the third moult" 

 [i. e. at the end of the fourth stage] - 'a por- 

 tion of the larvae spin up; these all produce 

 male moths. The female caterpillars , . 

 undergo a fourth (and as, it appears from 

 more recent experience, in some instances 

 even a fifth) molt . . ." That is. male larvae 

 have four stages and female, five or six In 

 my experience, male larvae have six s 

 and female six or seven (usually seven) just 

 as is the case also with O- definita Pack, and 

 O. cana Hv. Edw. which I have described. 



I give briefly the stages as I have observed 

 them. 



Egg. — Nearly spherical, smooth, not shiny ; 

 color yellowish white, a large round pale 

 brownish spot at the vertex surrounded by a 

 ring of the same color. Diameter 0.9 mm. 

 Laid in a mass on the cocoon of the J moth 

 and covered with froth which becomes hard 

 and white when dry. 



First larz'al stage. — Head shiny, pale, 

 subtranslucent brownish, darker on the ver- 

 tex: ocelli black, mouth brown ; width 0.5 mm. 

 Body pale whitish, the warts concolorous, 

 except the subdorsal ones which are black- 

 ish, those on joint 2 larger than the others. 

 An indistinct white dorsal line; venter and 

 legs pale. Hair very long, irregular, no 

 brush-tufts, pencils nor retractile tubercles. 



Second stage. — Head pale reddish brown ; 

 width o.S mm. Body pale yellowish, a sub- 

 dorsal black band and a broad dorsal one on 

 joints 9-12; a brick red dorsal shade on 

 joints 4 and 9; a few plumed black hairs from 

 the subdorsal warts on joint 2 and the 

 dorsal on joint 12 ; retractile tubercles pre- 

 sent, one each on joints 10 and 11 dorsally, 

 pale yellowish, just tinged with red, but dis- 

 tinct. Cervical shield yellowish. 



Third stage. — Head brownish red. mouth 

 darker; width 1.1 mm. Cervical shield 

 orange. Body pale yellow dorsally. a broad 

 dark gray lateral band and black dorsal band, 

 triple on joints 3 and 4, wide on joints 5-8 



