, . The . . 
South Australian Naturalist. 
VOI.. V. ADELAIDE, AUGUST, 1924. No. 4. 
NOTES ON EGGS, HABITS and MIGRATION of some 
AUSTRALIAN AQUATIC BUGS. 
(Corixidae and Notonectidae.) 
By HERBERT M. HALE, South Australian Aluseum. 
In none of the fifteen known species of Australian water- 
boatmen is the complete life-cycle described; nevertheless, the 
eggs in themselves form ri] interesting study. These are inverted 
top-shaped, or of elongate sub-oval form, and are always attached 
perpendicularly from their support. Usually the base is fas- 
tened by a pad of adhesive material to weeds, stones and other 
submerged objects. In this publication (1) reference has already' 
been made to the use of water-boatman eggs as food in Mexico; 
the eggs deposited in such huge numbers were described b / Kir- 
caldy (2). They are somewhat unusual in that they are sup- 
ported by a more or less extensile, but short, stalk (Text fig. 1, a). 
Four Corixid genera — viz. Arctocorisa, Porocorixa, Micro- 
necta and Diaprepocoris — are represented in Australia. The 
ova and other stages of the life history of members of the last- 
named genus are unknown. Those eggs of our species of Arcto- 
corisa and Microvecta which the waiter has had opportunity of 
examining are of the more usual Corixid type, more or less top- 
shaped, and glued at the bluntly rounded end to their support 
(Text fig. 1, b). 
In the case of Porocorixa, however, there is a difference in 
the method of attachment. Some time ago, the writer (3) figured 
some water-boatman eggs taken from the Torrens River, in April, 
1921, at a spot where, at that time, our largest member of the 
genus (P, eurynoviej was breeding in considerable number. As 
the larvae which emerged from the eggs were larger than the 
first instar nymphs of other Australian forms, it is^ certain that 
the species mentioned was responsible for the ova. They are of 
an irregular oval shape and each is borne on a long, transparent, 
thread-like stalk, connected to the adhesive disc attached to plant 
stems (Text fig. 1, c). This stalk, although fragile in appear- 
ance, is strong, flexible and elastic. The eggs taken as a whole 
superficially recall to mind those of the lace-w'ing flies. A year 
later Dr. H. B. Hungerford (4), in a paper dealing with the eggs 
of w^ater-boatmen, described and figured the hitherto unknown 
