438 



PSYCHE. 



[April iS93i 



LIFE HISTORY OF ORGYIA GULOSA HY. EDW. 



BY HARRISON G. DYAR, BOSTON, MASS. 



According to my observations, the black; width 0.4 mm. [Probably was really 

 larvae of this species have four or occa- °-5 mm. The measurement was not verified 

 sionally five stages for S , and five for 9 

 moths. This corroborates the published 

 account of 0. leucostigma by Prof. 

 Riley which I was not able to confirm 

 from New York specimens of that 

 species. Judging by analogy, therefore, 

 O.gulosa may elsewhere, or in different 

 seasons have six stages for $ , and seven 

 for ? moths, as I have observed to be 

 the case in all other species of Orgyia 

 which I have yet reared. The young 

 larva of O. gulosa may readily be dis- 

 tinguished from that of O. carta; but 

 not so with the mature larvae. In fact 

 the mature larvae of these two species 

 are hardly distinguishable. The only 

 characters that will serve to separate 

 them are that O. gtilosa usually has 

 a lateral row of yellow spots which 

 are wanting in O. cana and the warts of 

 row v (substigmatal) are brown in O. 

 gulosa and red in O. cana. But these 

 characters may not always be constant. 



Orgyia gulosa Hy. Edw. 

 1S81 — Hy. Edw., Papilio, i, 64. 



1881 — Bull., Ann. mag. nat. hist. (5) viii, 

 316. 



1882 — Grote, Check list, p. 17, no. 439. 



1890 — Packard, 5th rept. U.S. ent. comm. 



P- *34- 



1891 — Smith, List lep., no. 1 151. 



1892 — Kirby, Cat. Lep. Het. , i, 495. 

 Egg. — Almost spherical, smooth shining 



white, with a faint brownish spot and ring at 

 the top; diameter 1 mm. Laid in a mass on 

 the cocoon of the female moth and covered 

 with down from her body. 



First larval stage. — Head round shining 



as I lost the cast head case."] Body pale 

 purplish black, nearly white on the dorsum 

 of joints 3 and 4 and yellow on joint 9; on 

 joints ioand 11, a large brick red dorsal spot, 

 but no elevations to represent the retractile 

 tubercles which are absent. Warts normal, 

 row i small, row iv represented by small pale 

 dots. The subdorsal warts on joint 2 are 

 large with swollen bases. Each wart bears 

 several black hairs, longer from the sides and 

 extremities. 



Second stage. — Head black, a line above 

 the mouth and basal joints of antennae white ; 

 width .7 mm. Body black, dorsum of joints 

 3 and 4 pale yellow, of joint 9 darker yellow; 

 tips of abdominal feet pale orange. Subdor- 

 sal warts on joint 2 large, but bearing only 

 ordinary hairs. On joints 3 and 4 a few pale 

 hairs dorsally and on joints 5-7 a few black 

 ones, converging over the dorsal line but not 

 numerous enough to form tufts. Warts all 

 black; retractile tubercles on joints 10 and 11 

 present, large, orange colored. Side hairs 

 long, black, mixed with paler ones. 



Third stage. — Head as before; width 1.2 

 mm. Body black laterally, the dorsum 

 broadly pale yellow, but transversely streaked 

 with black at the middle of each segment. 

 These bands become broader posteriorly till 

 they cover most of the segment. The yellow 

 is also replaced by black in the segmental 

 incisures and broadly on joints 5-8. Warts 

 blood red, not very bright, rows v and vi and 

 the anterior dorsal ones partly black. Re- 

 tractile tubercles coral red; cervical shield 

 black. On joint 2 subdorsally and on joint 

 12 dorsally arise pencils of black plumed 

 hairs* about 1 mm. long. On joint 5 a black 



*These h;iirs differ from the other hairs of Orgyia in 

 that the minute branches or barbs, with which they are 

 all furnished, are longer and crowded more closely 

 together near the tips of these hairs, giving them the 

 appearance of being plumed at the end. 



