297 



THE PEA AND BEAN WEEVILS. 



The life-histories of these two insects have been comparatively well 

 known to economic entomologists for many years, bnt even in recently 

 l)ublislied acccmnts some misstatements are to be fonnd, and there is 

 little wonder that with practical people the qnestion should still be 

 raised as to whether either or both will continue to breed in stored 

 seeds. The text for this resume of tlie main facts in the life-histories 

 of these insects will be found in the following- communication from 

 Peter Henderson & Co., the large seed dealers in New York City: 



We send some beans infested with what we suppose is the Bean Weevil {BruclntH 

 fabw). The ravages of this insect are enormous and wc think are increasing. We 

 are led to believe that the eggs are laid on the pod when growing, and that it is in 

 the larval stage that all the feeding and consequent damage is done; further, that 

 after the larval and feeding stage it passes into the chrysalis, and there remains 

 dormant until spring or artificial warmth leads it to emerge from the place prepared 

 by the larva. We also an; of the opinion that the adult insect is perfectly harmless 

 to any seed beans, notwithstanding the opinion of one of our large growers, who 

 claims that "the bugs travel from bag to bag and bin to bin and eat the holes," 

 similar to the ones in sample sent. Our limited knowledge of entomology leads us 

 to su])pose his theory is totally impossible, but, seeing that such an important issue 

 is involved, we take the liberty to ask the benefit of your knowledge. * * 



Comparatively full accounts of both the Pea Weevil and the Bean 

 Weevil were published in the Third Report on the Insects of Missouri 

 (pp. 44 to 50 and 52 to 56), and from these accounts and our subse- 

 quent jiotes we have prepared the following summary: 



THE I'EA WEEVIL {Bruchus pisi Linn). 



The adult Pea Weevil is shown at Fig. 40ft, with the natural size 

 indicated at the small outUne 

 below. It is about 5 mm. long 

 and its general color is rusty 

 black, with more or less white 

 on the wing-covers, and a dis- 

 tinct white spot on the hinder 

 part of the thorax, near the 

 scutellum. The beetles begin 

 to appear about the time the cL 



„ • ui 11 P'iG. 40.— Pea Weevil: 6, adalt; c, fall- grown larva; d, 



peas are in blossom, and when p^^p^,^ ^ ^^^ ^^^^..^^ ^^.^ ^„j^ enlarged, nat. size indi- 



the young pods form the fe- tatedb\ smaller figures below (after Curtis). 



males lay their eggs upon the surface without attempting to insert them. 

 These eggs, as shown at Fig. 41, are deep yellow in color, 1.5 mm. long, 

 three times as long as wide, fusiform, i)ointed in front, blunt behind, 

 but larger anteriorly than posteriorly. They are fastened in front by 

 some viscid fluid which turns white in drying. It is probable that the 



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