90 



In writing about egg-laying, in connection with the Rock}- 

 Mountain Locust, Professor Riley sa\'s: "The eggs ma}^ be 

 laid in almost any kind of soil, but b^v preference the}' are laid 

 in bare, sand}^ places, especially on high, dry ground, which is 

 tolerably compact and not loose. It is often stated that they 

 are not laid in meadows and pastures, and that hard road 

 tracks are preferred; in truth, however, meadows and past- 

 ures, where the grass is closely grazed, are much used for ovi- 

 positing b\" the female, while on well-traveled roads she seldom 

 gets time to fulfill the act without being disturbed. Thus a 

 well-traveled road may present the appearance of being per- 

 fectly honeycombed with holes, when an examination will show 

 that most of them are unfinished and contain no eggs ; where- 

 as a field covered with grass stubble ma}' show no signs of 

 such holes and yet abound with eggs." What is said above 

 concerning the smaller Rocky Mountain Locust and its egg- 

 laying habits, will fit equally well the much larger .\rgentine 

 Locust as it normallv carries out this mission in its life. 



Daring the past season, however, the climatic conditions, 

 coupled with the general health of the locusts, caused a varia- 

 tion in these insects' egg-laying habits in some portions of the 

 country. Instead of confining their attentions to the more com- 

 pact soils of road-sides, pastares and more or less bare camp, 

 the females congregated in wheat-fields and other localities 

 where the soil was ratlier loose. Mere they left their eggs in 

 countless millions. The reasons for this variance being possibly 

 due to the excessive drought that prevailed at the time combin- 

 ed with the fact that a sort of disease in the insects' oviposi- 

 tors prevented their digging to a great extent. In some localities 

 the eggs were even extruded without the slightest attempt 

 on the part of the females to bury them beneath the surface. 

 Even during the nights, as the insects roosted upon trees and 

 fence-posts, the eggs w-ere laid. Sometimes in the morning the 

 ground beneath Avas strewn with the dropped eggs and the 

 glutinous froth}' covering that had been also evacuated from 

 the body as if a natural deposit had been made. 



After having selected a suitable place for her eggs the fe- 

 male locust forces a hole in the ground by means of two pairs of 

 horny valves which open and shut at the tip of her abdomen. 

 Again quoting from Professor Riley in his report on the North 

 American migratory locust, we have the following words : 

 « Witli the valves closed she pushes the tips into the ground. 



