de: 
THE OVIPOSITION RESPONSE OF INSECTS 7 
importance to the potato tuber moth (Pthorimaca operculella). 
In France, Picard (58) states that it generally lays its eggs in the 
cavities which surround the buds on the surface of the tuber, 
in incisions of the skin, or on the clumps of dried earth which 
adhere to the surface. It will also oviposit on the foliage of Ver- 
bascum and Cynoglossum which is felted and plaited, in preference 
to that. of Linaria, for although the latter is more closely allied to the 
Solanaceae than Cynoglossum, its leaves have smooth surfaces. In 
laboratory experiments, the moths often laid a part of their eggs 
on the muslin sides of the cage, even when potatoes were available, 
but eggs were placed only exceptionally on the glass walls. Graf 
(29), who has studied the potato tuber moth in America, likewise 
reached the conclusion that oviposition was stimulated by rough- 
ened surfaces. The Angoumois grain moth (Sztotroga cerealella 
Oliv.) does not require the presence of grain as a stimulant for 
egg laying, but, in captivity, will readily oviposit between strips 
of cardboard. Usually all the eggs are deposited in the crevice be- 
tween the strips (75). Dewitz (20, 22), while pointing out the 
possible role of odor in the attraction of the gravid female of 
Cochylis ambiquella, also states that oviposition on the grapevine 
bud may be attributed to a contact stimulation. In another paper 
(21 p. 233) he quotes Marchal to the effect that the female of 
Polychrosis botrana is guided during oviposition upon the smooth 
surface of the grape by the tactile power of the abdomen... Ovipo- 
sition would not take place on grapes covered experimentally with 
powder or a sticky mass. The experiments of Adolph (7) on 
Drosophila melanogaster show that the texture of the substance with 
which the gravid female comes in contact exercises a marked effect 
upon the quantity of eggs laid. Boiled agar was more potent in 
this respect than any of the solutions which were used to test the 
effect of taste, odor, or a combination of taste and oder. The 
character of the nidus also has a very evident influence upon the 
oviposition of the house fly (Jfusca domestica). Under appropriate 
conditions, pine sawdust is considerably less attractive than timothy 
chafl or horse manure, and moist’ absorbent cotton (containing 
ammonium carbonate only) was oviposited upon only once in 11 ex- 
periments (63, 64). Some observations by Picard (60) on the ovi- 
position of Pimpla instigutor ., a hymenopterous parasite of the 
ehrysalis of Pieris brassicae I... and of certain other Lepidoptera, 
are interesting in this connection. If an old chrysalis shell or a 
eylinder of white paper is coated with fresh blood from a chrysalis 
of Pieris, the parasite will pierce it with its ovipositor. The stimu- 
Ins is olfactory, but according to Picard the actual deposition of 
the egg depends upon a tactile stimulus produced by the, resistance 
of the living tissue within the chrysalis. Indeed, a chrysalis shell 
or a hollow cylinder of paper may be many times perforated by the 
ovipositor, but never will an egg be laid. The impartance of tactile 
stimuli in the oviposition response of Habrobracon juglandis has 
recently been shown by Hase (Die Naturwissenschaft. Jahrg. 11, 
Heft 39, pp. 801-806, 1923). Touch is probably the directing sense 
in the oviposition behavior of Habrocytus (6/). 
In a recent publication, Howard (36, p. 36-37) declares that the 
stimulus for oviposition in certain chalcidoid parasites of gall-mak- 
