98 FIRST ANNUAL REPORT OF THE STATE ENTOMOLOGIST. 



number to the number of the cocoons — ifc was found that there 

 were fifteen males and eighteen females. The mystery of the deficient 

 head-cases was solved. The fifteen male larvaj had spun up in their 

 cocoons after three molts, and the females had undergone an addi- 

 tional molt before maturing and forming their cocoons. 



That a female moth may undergo one molting more than the male 

 had been before noticed. Prof. Riley records it as the rule in the de- 

 velopment of Orgyia leucostigma, the white-spotted tussock mothj 

 which deposits the white froth-coated egg-masses upon the trunks of 

 the elm and horse chestnut trees, which its caterpillars injure so seri- 

 ously and often defoliate in Albany and other of our cities. Of this 

 species he states* that the male caterpillars spin up in cocoons about 

 six days before the females, which continue their growth until they at- 

 tain about twice the size of the males. 



An additional molting of the female Orgyia antiqua Linn., in Eng- 

 land, has recently been recorded {Ent. Month. Mag., xix, p. 210). 



Observations made by me during the last summer render it almost 

 certain that this same sexual diflference in the moltings exists also in 

 Callosamia Prometlica (Drury). The cocoons which I have in my 

 possession, obtained from a brood of larvae raised last summer, will per- 

 mit of a positive determination on this interesting point. 



Annual Sroods. 



There are two annual broods of this species. The hibernating eggs 

 produce moths in June and July, which at once deposit eggs to 

 give the second brood of moths in the month of September. I have 

 captured them, at rest upon trees, at different times between the 1st 

 and 6th of September. Eggs of the first brood, obtained during the 

 first week in July, showed some black spots on the 9th, depressed sides 

 on the 12th, and changed to a pearly- white color a day before their 

 hatching on the 19th. 



Distribution. 



It does not appear to be a widely distributed species. It is known 

 to me only from New York and the New England States. It seems to 

 be much more rare and limited than its longer known congeneric 

 species, Planosa velleda Stoll, which is occasionally met with upon 

 apple, elm, and a few other trees, throughout the Eastern and Middle 

 States, extending into Georgia (Smith-Abbot), Kansas (Snow), and 

 Illinois (French). 



Remedies. 



The rarity of this insect renders it unnecessary to indicate means 

 for its destruction. It probably will never appear as a pest, unless a 



* First R&port on the Insects of Missouri, 1869, p. 145. 



