6 BULLETIN 1324, U. S. DEPARTMENT OF AGBICULTTJEE 



eluded 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 

 through the specific odor of the larval food plant, Galium. Titschack 

 (77) found that the color of wool stuffs is not a factor in deter- 

 mining egg laying in the webbing clothes moth (Tineola biselliella 

 Hum.). 



AIR A.VD WATER CURRENTS 



Aquatic and aerial insects are oriented in their environment by 

 the movement of the medium surrounding thejm. It seems probable 

 that ovipositing insects are also affected by stream or air movement. 

 Wardle (81) states that wind is antagonistic, to the oviposition of 

 blow-flies. The cyrtid fly Pterodontia favipes 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 appropriate 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 (16) 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 animal 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 suitable 

 material is necessary to bring about the release of the egg case (32) . 

 According to Folsom (25 p. 349), some species of grasshoppers 

 prefer hard-baked soil for oviposition. The migratory grasshopper 

 (Locusta migrator/a L.) in Russia evidences a choice between dif- 

 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 grasshop- 

 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 (13) . 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 larvse. 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 



