22 



REMEDIAL MEASURES. 



Plowing. Plowing is of great value w changa control, for large 

 numbers of the insects are exposed to chickens, lizards, and other 

 enemies. In addition, egg chambers are broken up and some eggs 

 exposed to the sun, a few hours' exposure to the direct rays of the 

 sun apparently preventing eggs from hatching. 



Trapping. During October, November, and December changas 

 take flight in large numbers, most commonly on cloudy, overcast 

 evenings. The insects appear in largest numbers just after dusk, few 

 flying after 9 or 10 o'clock. The surprising fact was noted in cap- 

 tures at lights at Mayaguez and at Rio Piedras (on a single evening 

 at the latter place) during October, 1916, that the females outnum- 

 bered the males more than two to one. This disproportion fell some- 

 what with later captures, but females were still in the majority in 

 January, 64 per cent of the total catch belonging to this sex. A large 

 proportion of the females captured during the fall were sexually 

 immature. 



A season's experience with trap lights has indicated that their use 

 is not generally practical against the changa. It is only on the rare 

 occasions when the mole crickets fly in large numbers that it will 

 pay to operate a light trap, as at other times the catch will be very 

 scattering. Observation will determine whether the insects are 

 abroad in sufficient numbers to make the running of the light 

 profitable. 



The trap light should be very bright, and the pan of oil and water 

 placed beneath should be as large as can be had. As the mole cricket 

 is not attracted to the light, but only to its vicinity, it would pay 

 in case only a small pan is available, to have the changas that fall 

 outside the receptacle picked up. It is useless to keep the light going 

 after 10 o'clock. 



Large bonfires in the fall of the year are said to attract and de- 

 stroy large numbers of the changa. 



Traps made by sinking wide-mouthed bottles in the earth up to the 

 mouth were found to be useless, even when baited with cornmeal. 



Burlap bags are said to be successfully used as traps for mole 

 crickets in the Isle of Pines. The bags are laid flat on the ground, 

 inspected early each morning, and the crickets found under them 

 are killed. Some writers state that mole crickets congregate be- 

 neath compost heaps and can be captured there in large numbers. 



Flooding. It may sometimes be found practical to flood areas 

 easily reached by irrigation canals. Flooding formerly practiced 1 



* According to Mr. Holger Johansen. 



