206 



BEETLE PESTS. 



FIG. 243. 



The G-reen Blister JBeetle. 

 (Slightly magnified.) 



beetle similar in shape but of a dull brown colour. These two damage a 

 variety of crops, including sorghum, rice, kutki (Panicum miliare), bajra 



(Pennisetum typUoideum), etc., by destroying 

 the flowers; large numbers emerge as these 

 crops flower and settle on the head, biting the 

 anthers and stigmas so that seed is not 

 formed. 



This results in a large or total loss of 

 grain. The attack is very sudden, and 

 requires to be checked at once. The insects 

 feed principally in the morning, hiding in the 

 earth or on the plants during the hot part of 

 the day ; they remain only a few days and 

 again disappear. This form of damage is by 

 far the most important caused by these beetles 

 and is observed or reported yearly in some dis- 

 tricts of India. 



No other species are known to be destruc- 

 tive in India although others will probably be 

 found to be so. Several blue species are common in the plains but perhaps 

 appear at a time when no crops are in flower. 



The life history of these beetles is unknown, but there is scanty 

 evidence that it will prove to be similar to that of European and Ameri- 

 can species. The eggs of two Indian species are laid in large masses 

 on the soil and active grubs hatch which run about the surface. The 

 life histories of those worked out elsewhere are of extreme interest, 

 being passed in the nests of bees or wasps, or in the egg masses of locusts. 

 The active larva that hatches from the egg attaches itself to a bee 

 and is carried to its nest, or seeks out the egg mass of a locust. In all 

 cases known the larval life is a semi-parasitic 

 one, and there is a curious metamorphosis in 

 the larval life, the larva assuming two or more 

 distinct forms at successive periods. 



Blister beetles are useful in medicine, the 

 oil of certain species having the power of blis- 

 tering the human skin. The extract of the 

 dried beetle is used for this purpose. In India 

 these beetles are used in a somewhat similar manner. In Baluchistan, 

 for instance, the " Gojak " beetle l is soaked in milk and the fluid poured 

 on the bald spots to cure mange (R. Hughes-Buller) . When the beetles 

 1 Closely allied to Mylalris pustulate. 



FIG. 244. 

 Brown Blister Beetle. 



