30 



Fig. 18. — Field locust (Orchelimum a gile)( original). 



Valley in Louisiana, and were reported by Mr. George W. Arnold, of 

 Vanceville. La., as injuring alfalfa. No opportunity was presented 



for a study of its life history and 

 habits. 



Field locusts. — In August, Sep- 

 tember, and October from among 

 the coarse ditch grasses and those 

 of swamp and waste places come 

 the rasping sounds and almost con- 

 tinuous buzz of the field locusts. 

 Not much attention has been paid 

 to these long-horned grasshoppers 

 or locusts. In ordinary seasons they are not prone to wander from the 

 ditch banks, but when the differential prevails, they are forced into 

 the crops in search of food. In 1898 and 

 1899 considerable damage was done. The 

 prevalence of a species of Orchelimum may 

 be imagined when in certain sections of the 

 Delta, particularly near Mound Landing, 

 Miss. . hundreds of acres of dry cotton stalks 

 were found to contain numbers of eggs in 

 every branch and twig (see fig. 19 showing- 

 general appearance of punctured stalks and 

 position of exposed eggs). These eggs were 

 also found abundant in the tassel stalks of 

 corn in widely distributed fields. 



The eggs hatch during the latter part of 

 May and continue until June 20. Moisture 

 has much influence upon hastening incuba- 

 tion and hatching. In cages the stalks of 

 cotton were moistened every few days, and 

 after each dampening the young emerged 

 more numerously. The exact number of 

 molts was not determined. After molting 

 the }^oung devour the cast skin and fre- 

 quently they have been found devouring 

 one another. Maturity is reached very ir- 

 regularly owing to the difference in the time 

 of hatching and of the variations of devel- 

 opment. The form most commonly found 

 upon Dahomy was Orchelimum agilt (sec 

 fig. 18). It matures from the middle of 

 July until September 1, deposits eggs from 

 fifteen to thirty days after reaching the adult, and winters in the egg 

 conditio!). In 1899 Orchelimum <i</il> was a real enemy to cotton. 



Fig. 19.— Portion of cotton stalk 

 showing punctures and eggs of 



orchil iiu inn agiU -original |. 



