AUTHOR’S ABSTRACT OF THIS PAPER ISSUED 
BY THE BIBLIOGRAPHIC SERVICE, JULY 12 
EGG-LAYING REACTIONS IN THE POMACE FLY, 
DROSOPHILA! 
EDWARD F. ADOLPH 
INTRODUCTION 
When and where animals lay their eggs, a problem which 
has been studied under field conditions by many observers, 
demand analysis through experiment into terms of response to 
sensory stimuli. The process is more complicated than some 
other responses, and has been supposed to involve an element 
of foresight not usually attributed to many other activities. 
Marine invertebrates in general extrude their eggs regardless 
of immediate surroundings; when the eggs are mature they are 
shed. Among insects there are many grades of behavior as 
regards egg-laying, from the indiscriminate distribution by silk- 
worm moths to the preparatory building and provisioning of 
nests by wasps. 
Among Diptera each species has fairly distinctive habits. 
The Hawaiian melon fly (Bactrocera), studied by Back and Pem- 
berton (14), lays eggs just beneath the surface of fruit, flower, or 
stem of pumpkins and squash, depositing many eggs in one day, 
but only on one day in every six or eight. The Mediterranean 
fruit fly (Ceratitis), studied by the same authors in Hawaii 
(15a), laboriously bores through the thick skins of citrous 
fruits, and lays a few eggs nearly every day for many weeks. 
The house fly (Musca domestica L.) lays its eggs in large numbers 
wherever moist fecal or other decaying animal material is present 
(Hewitt, ’08), while the blow fly (Calliphora) lays wherever 
carrion or the odor of decaying meat is found (Lowne, ’90). 
1 Contributions from the Zodlogical Laboratory of the Museum of Compara- 
tive Zodlogy at Harvard College, no. 322 
327 
