742 Journal op the Department op Agriculture. 



Mr. Claude Fuller, Assistant Chief of the Division of Entomology, 

 has on a number of occasions found beetle larvae in the egg masses of 

 locusts in Natal, but the specific identity of the larvae is unknown. 



Blister beetles have remarkable life-histories, in that they exhibit 

 the phenomenon of hypermetamorphosis, i.e. they pass through more 

 stages during their growth than do the ordinary beetles or other 

 insects. Thus, instead of egg, larva, pupa, and adult, there are three 

 different larval forms, a pseudopupa, and a pupa before the adult 

 stage is reached. 



Food Habits and Status of the Beetles as Pests. 



Our common Mylabrids injure the blossoms of plants, but since 

 the larvae are perhaps beneficial the question arises: Just how much 

 damage do the adults really do, and is it enough to make the destruc- 

 tion of the beetles advisable? Opinions will differ on this question. 



Many years ago (1893) Dr. Peringuey remarked (4) that " It is 

 so seldom that a beetle proves to be useful to the farmer that, were 

 they plentiful in my garden, I would purposely sow a patch of beans 

 for the delectation of Mylabris, knowing full well that such a small 

 favour would be amply repaid." 



On the other hand, the late Dr. J. B. Smith, an eminent econom'c 

 entomologist, leferring to some leaf-eating American blister beetles, 

 stated that: "In the larval stage they are beneficial, in so far as 

 they feel upon tiie eggs of grasshoppers, but it is questionable whethiM; 

 this benefit overbalances the damage they do as adults, and I never 

 hesitate to advise prompt measures for their destruction" (5). 



With regard to the Indian species Fletcher makes the following 

 statement : " Blister beetles often do great damag*e to crops by devour- 

 ing the flowers and tender shoots. Cereals and leguminous crops are 

 especially subject to attack, and there seems to be some special attrac- 

 tion for these beetles in flowers of yellow colour. . . . Whether these 

 beetles are to be ranked as pests or beneficial insects is at present, how- 

 ever, an open question. In the adult state they certainly do harm to 

 crops. . . . If, therefore, the larva of a blister beetle destroys even 

 one egg-mass containing (say) forty eggs of a grasshopper the good it 

 accomplishes by so doing at this stage must be offset against any 

 damage it may do later as an adult, and the question we have to 

 answer is whether ihe damage tliat would have been done by the grass- 

 hoppers is greater tlian that done by the beetle that has destroyed 

 them. And for the present, at least, this must remain an open 

 question, and we can give Ihe blister beetles the benefit of the doubt " 



Although the damage done by tlie Mylabrids in gardens is often 

 rather small when compared with that done by the fruit beetles 

 (Cetonids), they are undoubtedly a great nuisance at times, eating 

 and defiling tlie blossoms of ornamental plants, especially roses. They 

 injure the blossoms of fjuii trees, but here it is a question of whether 

 or not the settiniJ of the fruit is interfered with, and not one of damage 

 to the beauty of the trees. The blossoms of beans, peas, etc., are also 

 attacked, the beetles being particularly fond of these. 



It has been the exi)erienco of the writer that the damage to plants, 

 as well as the number of beetles i)resent. is often over-estimated. It 

 is true that the blossoms are eaten, but are they entirely destroyed? 



