THE ENITHARES (Hemiptera-Heteroptera: Notonectidae) OF THE ...

354 Pacific Insects Vol. 10, no. 2
Academy of Sciences, Warsaw (WARSAW) ; Dr R. Froeschner, United States National
Museum, Washington (USNM) ; Dr G.E. Hutchinson, Osborn Zoological Laboratory, Yale
(YALE) ; Dr T.E. Woodward, University of Queensland, Brisbane (UQ) ; Dr I. M. Kerhzner,
USSR Academy of Sciences, Leningrad (LENINGRAD) ; Dr F. S. Truxal, Los Angles
County Museum, California (LA) ; Dr P.H. van Doesburg, Rijksmuseum van Naturlijke
Historie, Leiden, The Netherlands (LEIDEN) ; Dr H. Andersson, Dept, of Entomology,
Zoological Institute, University of Lund (LUND) ; Dr R. Benard, Museum d'histoire
Naturelle, Paris (PARIS) ; Dr E. Kyellander, Naturhistoriska Riksmuseum, Stockholm (STOCK­
HOLM) ; Dr H. Weidner, Zoologisches Staatsinstitut und Zoologisches Museum, Hamburg
(HAMBURG) ; Dr C. N. Smithers, The Australian Museum, Sydney (AMS) ; Dr K. S. Pradhan,
Zoological Survey of India, Calcutta (Zool. Sur. India) ; Bernice P. Bishop Museum,
Honolulu, Hawaii (BISHOP) ; Snow Entomological Collections, University of Kansas, Lawrence
(SECK) ; Mr E. S. Brown, c/o Dept, of Entomology, Brit. Mus. (Nat. Hist.) (E.S.B.) ;
Dr Marshall Laird, World Health Organisation, Geneva. Dr G. Gross, South Australian
Museum, Adelaide (SAMA) ; Dr A. Neboiss, National Museum of Victoria, Melbourne
(MELBOURNE) ; Mr A. W. Sweeney, Malaria Institute, Rabaul, T.P.N.G. Dr CH. Fernando,
Dept, of Biology, University of Waterloo, Ontario, Canada.
BIOLOGY
Little is known about the biology of Enithares. Nowrojee (1911) iov E. ciliata (F.) ( =
indica F. sensu Nowrojee) and Hoffmann (1931) for E. Sinica (Stal) give some data on
life histories. Both report that the eggs are laid on submerged plant tissue. Nowrojee
states that the eggs are glued on, not inserted in the plant. Enithares thereby closely resembles
some species of Notonecta (Hungerford 1919). The number of eggs laid is variable.
E. ciliata in an aquarium laid 8, E. Sinica "more than a dozen." I have a plant
stem on which E. woodwardi Lansbury laid 19 eggs in about 90 minutes in an aquarium.
Hungerford (1919) dissected a female N irrorata Uhler which was found to contain 252
ova, several of which were nearly ready for laying. It is not known if Enithares is as
prolific as this.
The Qgg of E. woodwardi is about 1.45 mm long, width viewed from above .65 mm.
Color in alcohol pale yellowish white. Shape, elongate rounded at both ends, anterior
pole slightly depressed around the curved, cylindrical truncated, micropylar peg. Hatching
line visible as a broken linear brown line extending from micropyle to caudal end.
Chorion hard, covered with hexagonal reticulations. The Qgg of Enithares is very similar
in general structure to that of Notonecta (Hungerford 1919).
The incubation period is variable. The period for E. Sinica varies between 9-26 days
(Hoffmann 1931). Nowrojee (1911) noted eye spots appearing just before hatching. The
data given by Hoffmann who includes a precis of Nowrojee's figures show that development
from hatch is dependant upon temperature - E. Sinica taking 38-49 days and E. ciliata
33-38 days, the period of the 5th instar being the longest. Hoffmann using isolated specimens
found that the highest mortality occurred in the first and second instars. E. Sinica
took 2 or more days to become fully pigmented after the last moult. Hale (1923) stated
that pale examples of E. woodwardi (=£*. bergrothi Montandon sensu Hale) confined in
aquaria eventually became black, other than head, part of the pronotum and legs.