October, '14] MOSHER and WEBBER: GIPSY MOTH LARVAL MOLTS 371 



times always produce male moths, that those that molt five times 

 always produce female moths, those that molt four times produce both. 



"It would thus appear that in Notolophus (Orgyia) antiqua Linn., 

 the female molts one time more than the male, a circumstance that 

 I have not seen noticed as occurring in any species, and that further 

 the molts may vary by one. " 



The results obtained by Doctor Chapman's experiments using 

 larvae of Notolophus (Orgyia) antiqua Linn, are corroborated by Mr. 

 J. Hillins,^ who conducted an experiment using larvse of the same 

 species. Mr. Hilhns found that one male molted three times; one 

 female molted five times, and one male and one female molted four 

 times. 



The variation in the pupation of another species is noted by Prof. 

 J. A. Lintner in his First Annual Report on the Insects of New York in 

 1882. In the lappet moth, Tolype lands Fitch., he found that the 

 males molted but three times while the females went through an addi- 

 tional stage. 



Prof. C. H. Fernald's experiments using larvse of the gipsy moth 

 are noted in the Report on the Gipsy Moth written in 1896. Out of 

 a batch of 55 newly hatched larvse used in this experiment, 52 com- 

 pleted their transformations v/ith the following results: 1 female 

 molted six times, 29 females molted five times, and 9 females molted 

 four times; 7 males molted five times, and 6 males molted four times. 



According to the experiment just related there was no variation 

 whatever in the lar\al form as to sex of this insect, and, moreover, 

 another distinct stage was observed. 



Morgan's "Experimental Zoology" has an interesting account by 

 Pictet pertaining to the external appearance of some species of lepi- 

 dopterous larvse in regard to sex. In one instance he states (page 43), 

 that in the larval form of Porthetria [Ocneria) dispar, the sexual di- 

 morphism is marked, but adds that this only occurs in the fully formed 

 caterpillars. In another paragraph he says, "The caterpillars of 

 P. dispar normally transform into chrysalids after the sixth molt. " 



The results of these experiments by Pictet are at variance with our 

 own in numerous ways. We have never observed any uniform differ- 

 ence between the two sexes in the larval form, except in the size of the 

 head and body. Our experiments would indicate that only female 

 pupse developed from sixth stage larvse. 



In the sixth stage the velvety black stripes running vertically on 

 each side of the clypeus are wider and more distinct but the size of the 

 head although varying somewhat is considerably larger than in the 

 fifth stage. 



lEntom. Month. Mag., 1881, V. 18, p. 86. 



