422 



PSl'CHE. 



[November — Decemlier i?90. 



9 1.2 1.6 2.2 3.0, r .73 

 [ -4 -5 -7 -9 •1-2 1-6 — 



- .91.2 1.6 2.3 



found \ 



I 



I 3-0 



NINE STAGES. 



Halisidota caryae Harr. calc. .^ •7-9 



1.2 1.6 2.0 3.6 3.4 4.3, r .78 



found .4 .6 — ^'^ 1.2 1.5 3.1 2.7 



3-4 4-4 

 Halisidota tcsselaris S. & A. calc. .5 



.7 .9 1.2 1.6 2.0 2.6 3.4 



4.3, r. 78 



r 1-3 1-7 -^■'^ 



found \ ^-"^' V^ '^'^ r ^ 



j .4 .6 .9 — 1 .6 2.1 2.6 



TEN STAGES. 



Pyrrharctia i sab ell a A. & S. calc. .4 .5 

 .7 .9 I.I 1.6 2.0 2.6 3.2 

 4.1, r .79 

 found .4 .5 .7 .9 1.2 1.6 3.2 2.6 

 3.6^3 ^_^ 



' It will be seen that I corroborate the obser- 

 vations of Mr. W. H. Edwards in giving four 

 stages to this species, and as my specimens 

 were bred in Rhinebeck, N. Y. the theory of 

 variation in the number of molts due to climat- 

 ic influence suggested by Mrs, Dimmock 

 (Psyche, v. 5. p. 29) does not appear to be 

 sustained. 



^ This measurement, 3.5 mm., is too small 

 as the larva was unable to cast its skin and 

 the head was dwarfed. 



* This is too large; it is possibly an error 

 of observation and was not verified. 



* An incorrect measurement. 1 find it 

 marked with an ( .'') in my notes. 



* A remarkable instance of excessive de- 

 velopment. I do not think any error was 

 made. The second example behaved in a 



normal manner as can be seen from what 

 measurements I ha\'e. 



® My observations do not agree with those 

 of Dr. Packard on this species, who finds six 

 stages. (Proc. Bost. soc. nat. hist. v. 24, p. 



534-) 



'The second example has the normal meas- 

 urement. Possibly I have made an error in 

 the first measurement. 



* It will be seen that in both examples no 

 series is followed, but both larvae became 

 unhealthy and died in the fifth and sixth 

 stages respectively which probablj' accounts 

 for the dwarfed dimensions of their heads. 

 This is one of the instances of abnormal de- 

 velopment which is readily distinguishable 

 from an error of omission. 



For examples of the latter see note C'^). 



In giving six stages to this species I cor- 

 roborate the observations of Mr. Beuten- 

 miiller (Ent. Amer. , v. 6, p. 75) but disagree 

 with Dr. Packard who finds but five stages. 

 (Proc. Bost. soc. nat. hist., v. 24, p. 525.) 



^ An erroneous measurement. It is marked 

 in my notes as carelessly taken. 



'" This larva died in the sixth stage and its 

 head is seen to have been dwarfed. 



" The last stage, width of head t,.}^ mm., 

 occurs only in larvae that produce female 

 moths and it is seen to be too small for the 

 series. I intend to make more observations 

 on this species and will not cominent on it 

 further at tiiis time. 



'- Examples of accidental omissions which 

 were not detected at the time and which would 

 have gone entirely unrecognized had it not 

 been for the measurements recorded. On 

 making calculations and observing the ap- 

 parent omissions I endeavored to obtain more 

 lar\'ae. No young caryae were to be had, 

 but some tesselaris^ carefully watched ex- 

 hibited the missing stage as may be seen 

 from the second example. 



'■* Probably an error. I found this larva 

 very difficult to measure and this particular 

 stage was not verified by measuring the cast 

 head as most of the others were. 



