THE OVIPOSITION RESPONSE OF INSECTS s 
E’phestia kuehniella Zell. indicate that oviposition is considerably 
delayed and the number of eggs reduced if copulation has not taken 
place. Guyénot (37) and Adolph (1) obtained evidence from Droso- 
phila melanogaster that mating is a stimulus for egg-laying; the 
former thought it was a mechanical stimulus because the first eggs 
deposited were frequently unfertilized. Picard (67) has also observed 
this effect in Phthorimaea and Hesperophanes griseus F. A recent 
work by Glaser (26) indicates clearly that association with the male 
sex stimulates egg production in M/usca domestica L. and Stomoxys 
calcitrans LL. Virgin females of the imported pine sawfly (Diprion 
stmiée Hartig) apparently wait 2 days before oviposition and 
although they can reproduce parthenogenetically, if not mated they 
lay only half as many eggs as fertile females (53). Mating is not a 
factor in the oviposition of many parasitic Hymenoptera (34, 61), 
nor in certain social Hymenoptera.” | 
INTERNAL PERIODICITIES 
Adolph cites the work of Back and Pemberton (3) on the melon 
tiy (Bactrocera cucurbitae Coq.) to show that internal periodicities 
may be responsible for the intermittent deposition of eggs by cer- 
tain species. Such periodic egg-laying occurs in other insects (9) 
though few references to it have been found. Bishop, Dove, and 
Parman (&) mention that the house fly (Afusca domestica) lays eggs 
at 8-day intervals. 
EXTERNAL INFLUENCES AFFECTING OVIPOSITION 
TEMPERATURE 
Temperature influences the rate of many life processes, among 
which may be counted the activities connected with oviposition. 
Within the range of each species there is probably an optimum tem- 
perature for egg-laying. In the alfalfa weevil (Phytonomus posti- 
cus Fab.) mean daily oviposition follows in general the curve of mean 
daily temperature (57); a similar relation holds for the cctton boll 
weevil (Anthonomus grandis) (76). A reduction of 3° or 4° C. has 
been observed to lengthen the oviposition period of Vomécus (Ips) 
typographicus L. from 1 to 8 days (35). <A cool night retards the 
oviposition of Hypera punctata Fab. and it ceases between 7° and 
10° C., according to Hudson and Wood (39). <A recent study by 
Detouches (/9) on the wax moth (Galleria mellonella L.) shows how 
markedly temperature may affect the quantity of eggs laid. At 87° 
2 Some additional instances of fertility as a stimulus for oviposition have come to 
light since the above was written. According to Baker and Dayidson (Jour. Agr. Re- 
search, vol. 6, pp. 351-360, 1916), the female of Hriosoma pyricola Baker and Davidson 
fails to deposit the winter egg unless fertilized directly after the last integument has 
been cast. Hippodamia 13-punctata L. will oviposit without being fertilized but searcely 
one-fourth of the usual number of eggs are laid (Cutright, Ann. Ent. Soc. Amer., vol. 17, 
pp. 188-192, 1924). Sen (Rept.. Proc. 5th Ent. Meeting Pusa, February, 1923, pp. 
215-225, Calcutta, 1924) was not able to obtain eggs from unfertilized females of 
Aedes (Stegomyia) albopicta Skuse even after the insects were allowed to bite and 
suck blood. _ Studies on Chlorops taeniopus Meig. by Frew (Ann, Appl. Biol., vol. 11, 
pp. 175-219, 1924) show that unfertilized females commence ovipositing 10 to 12 days 
after emergence, while fertilized females begin laying in 4 to 5 days. Unfertilized flies 
alse lay fewer eggs than fertilized flies. Apparently the mite Tyroglyphus mycophagus 
(Mégnin) will not lay eggs unless if has been fertilized (Schulze, Zeitschr. wissen. 
Biol, Abt. A. Morph, and Okologie, 2, Heft 1 and 2, pp. 1-57, 1924). It is not yet 
clear whether this stimulus is a mechanical one, as Guyénot has suggested, or an internal 
one resulting from substances transferred to the female during coition. 
