6 BULLETIN 1324, U. S. DEPARTMENT OF AGRICULTURE 
cluded that two factors were necessary to induce Macroglossum to 
oviposit, an optical factor, effective at a distance through yellow 
and green light and a chemical factor operating near at hand 
thr ough the specific odor of the larval food plant, Galum. Titschack 
(77) found that the color of wool stuffs is not a factor in deter- 
mining egg laying in the webbing clothes moth (7%neola biselliella 
Hum. % 
ATR AND WATER CURRENTS 
Aquatic and aerial insects are oriented in their environment by 
the movement of the medium surrounding them. It seems probable 
that ovipositing insects are also affected by stream or air movement. 
Wardle (SZ) states that wind is antagonistic to the oviposition of 
blow-flies. The cyrtid fly Pterodontia flavipes Gray deposits its 
eggs on the leeward side of trees (45), in which location it may be 
oriented by air movement. 
SURFACES 
In many insects, contact with an appropri iate surface seems to 
be a necessary prerequisite for oviposition. According to Loeb (49), 
a highly developed stereotropism exists in the segments of the repro- 
ductive organs of animals, and further there are indications that 
contact with a solid affects the behavior of living matter through 
an influence on the rate of certain chemical reactions. Crozier and 
Moore (1/6) show that the response of diplopods to surfaces in 
contact with the body is essentially like the response of a positively 
heliotropic animal to light; that is, the ay turns its head 
toward the side which is in contact with a solid surface. When both 
sides are stimulated by contact with surfaces of equal extent, the 
movement of the animal is along a straight path. 
In the cockroach Periplaneta americana L., contact with ote ee 
material is necessary to bring about the release of the ego case (32). 
According to Folsom (25 p. 349), some species of. grasshoppers 
prefer hard-baked soil for oviposition. The migratory grasshopper 
(Locusta migratoria L.) in Russia evidences a choice between dit- 
ferent kinds of soil. Isolated females insert the ovipositor into the 
soil a number of times before they deposit their eggs, and often a 
swarm which has alighted on soil too hard for oviposition will re- 
sume flight again (80). Baillon (4) also mentions that grasshep- 
pers choose between different types of soil for oviposition. The 
Mormon cricket (Anabrus simplex Hald.) is said to prefer a some- 
what firm but not very hard soil for this purpose (73). According 
to McColloch (50) the corn earworm moth (Heliothis obsoleta) 
deposits more eggs on corn plants which have rough hairy stalk and 
leaf surfaces than on plants with smooth surfaces. The moths were 
also induced to lay some eggs on cotton twine. Investigations of 
Benedict (7) and Titschack (77) on the webbing clothes moth 
(Tineola biselliella) suggest that the tactile stimulus may be the 
determining factor in the selection of a place for egg laying by 
this species. Any rough surface was observed by Titschack to call 
forth oviposition, regardless of the food value of the material for 
the larve. The moths with which Benedict experimented laid their 
eggs on cotton and silk as well as wool, the loose threads being es- 
pecially preferred. The character of the surface is apparently of 
