SOME GENERAL FEATURES OF THE METAMOR- 

 PHOSIS OF THE FLAG WEEVIL MONONY- 

 CHUS VULPECULUS FABR. 



JAMES G. NEEDHAM. 



I HAVE been for some time desirous of studying the develop- 

 ment of some beetle which would represent metamorphosis in 

 as complete a condition as is found within the order Coleoptera. 

 Last summer I found an abundance of the flag weevil (Monony- 

 clius vulpeculns Fabr.) in all stages ; and this furnished me the 

 opportunity for which I waited. The larvae of this beetle are 

 little fat grubs, which eat the seeds of the blue flag (Iris vcrsi- 

 color Linn.). They are sheltered from first to last within the 

 flag capsule and are very degenerate. They lack eyes, antennae, 

 and legs, as well as wings. They represent a sort of ecological 

 specialization, common among the higher insects, manifest in the 

 adaptation of life to very special situations, and of life history to 

 conditions of transient food supply. 



I. Life History. 



The life history of this long familiar species seems not to 

 have been fully made known. 1 While gathering my material I 

 was not seeking to determine the full life history, but now I find 

 that my collections and notes reveal it pretty completely. Col- 

 lected material gathered in at intervals of two or three days give 

 data as follows : Eggs were first found June 8. The beetles 

 had just begun to oviposit on the earliest of the flag flowers, first 

 opened that day. Larvae were first found June 29, at which 



1 Dr. John Hamilton published fragmentary notes on its life history in 1894 

 (" Mononychus vulpeculus and its Parasites," Entom. News, vol. v, pp. 287, 288), 

 describing oviposition and the form and feeding habits of the larva, and citing an 

 instance of great destructiveness on the part of two parasites, Pimpla inquisitor 

 Say and P. fterelas Say. 



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