184 Psyche [December 



wax-glands on the tegmina, and in the nymph they are numerous 

 on the pronotal hood. They occur in most positions where 

 "sensory-organs" also occur, and being also little crater-like 

 processes on the cuticle may sometimes be mistaken for the latter 

 organs. 



A fairly large quantity of the wax excreted from the various 

 cuticular glands was collected by boiling the cast skins of nymphs 

 with ether in a Soxhlet extractor, and the following data there- 

 from were kindly given by Mr. S. S. Peck, chemist at this experi- 

 ment station, 2 to whom also I am indebted for some tests of the 

 contents of the malpighian tubes given above: 



The wax is slightly soluble in alcohol and in ether, easily soluble 

 in benzene. It separates in crystal form. Sp. gr. at 17° = .0972, 

 at 90° = .0826. Melting-point 80°-83.5°. 



A quantity of leaves and bark from young stems of Eucalyptus 

 was extracted with benzene in the cold, and the liquid then evap- 

 orated, when a fairly thick film of resinous-wax was left on the 

 bottom and sides of the vessel. This residuum was green from 

 contained chlorophyll. The wax appeared to be similar in part 

 to that excreted by the malpighian tubes of the insect, and also 

 by the cuticular wax-glands. 



The total length of the adult alimentary canal from the begin- 

 ning of the oesophagus to the anus is about 35 mm., when not 

 unduly extended. 



Siphanta acuta appears to live about two months as an adult. 

 One individual fed well on a young growing Eucalyptus tree, 

 and moulted to adult on April 28, dying on July 1. Another 

 specimen was very near these dates, and both apparently died of 

 old age, the bright coloring having become very dull, in some parts 

 whitish, in others yellow-brown. The vivid yellow-green of 

 young adults becomes a glaucous green in older individuals. 

 Although in the early part of the year the eggs of this Flatid hatch 

 in about twenty days, in the fall they hatch in about ten days. 



The three tissues of the midgut — basement-membrane, epithe- 

 lium and intima — seem homologous with the corresponding 

 tissues of the stomodseum, proctodeum and body -walls. The 

 basement-membrane of the epidermis is chitinous, and that of 



2 Hawaiian Sugar Planters' Experiment Station. 



