SECTION VI. — NATURAL ENEMIES 01' THK FROGIIOPPER. 7!) 



Progs and Toads. 



The comparative scarcity of these animals in the cane fields has also 

 been put down to the introduction of the mongoose. Although this may 

 be partially true {see p. 88) once more the effects of agricultural processes 

 must not be overlooked, and in the case of these animals the mo.-:t 

 important factor is increased drainage which reduces their breeding places. 



In some moister localities they are still common and frequently vi-it 

 the light traps to catch the adult froghoppers attracted thereto. 



As with the lizards an accurate investigation of tlieir food is needed 

 before definite conclusions can be drawn. 



Grasshoppers. 



There are several species of predaceous grasshoppers in Trinidad th it 

 eat froghoppers and other insects. These belong to two genera 

 Xiphidiiom (Conocephalus) and Pflugis. 



Xiphidium (Conocephalus) is represented in Trinidad, according to 

 the latest revision of Rehn & Hebard (Trans. Am. Ent. Soc. XII. p. 225) 

 by the two species, saltator and versicolor. 



The former of these is the most abundant and is often in very large 

 numbers in the traces through the cane fields, l)ut much less common 

 among the canes themselves. 



Fig. 17. 



Fig. 17 — A predaceous Grasshopper [Xiphidiuvt snUator). 



It is a medium-sized long horned grasshop[)er. green wich a brown 

 streak along the back. The ovipositor of the female is long and projects 

 beyond the wings which are frequently reduced in length (Fig. 17.) 



In addition to froghoppers it eats many other insects including 

 caterpillars, small Hymenoptera, and smaller specimens of its own 

 species. It also takes vegetable food. In J^ritish Guiana a closely 

 related species was found to eat the developing flowers of rice, and in 

 Hawaii X. variejiennc is partly vegetarian although also a valuable 

 destroyer of the injurious leafhopper. Closely related species are 

 abundant throughout ("entral America but always seem to prefer grass 

 to sugar cane as a place to live. 



Although most active during the day tiie adults are frequently found 

 in light traps put out in the cane fields during the night. 



The eggs of this grashopper are laid four or five together in slits in 

 the de-id leaf sheaths of grass and canes, but are easily distinguished 

 from those of froghoppers by their nuich larger size and cylindrical 

 shape. The eggs of X. varicpennc in Hawaii are parasitised by 

 Paraphel'uiHS xipliidii and the eggs of the Trinidad species are probably 



