CURCULIOS THAT ATTACK WALNUT AND HICKORY. H 



and resume activity in the spring in time to be on black walnut 

 trees when the male catkins of the walnut are fully developed. As 

 soon as the leaves and tender shoots appear the beetles attack them, 

 sometimes feeding rather extensively. Soon thereafter they begin 

 egg-laying in the young fruit. There is considerable variation in 

 the time the fruit sets on individual trees of the black walnut in 

 any locality and the beetles collect on the trees where the develop- 

 ing nutlets are at the stage just to their liking. This is immediately 

 after the female catkins on the point of the nut are beginning to 

 wither. Most of the eggs are deposited in nuts at this stage of 

 their development, although the beetles continue to oviposit to some 

 extent in nuts that are larger. 



The beetles live normally throughout most of the summer and 

 oviposit over a period of at least two months. Several over- 

 wintering beetles confined in screen cages placed over walnut branches 

 on the trees lived until the last of August. It is thus possible in 

 late summer to find the parent beetles and their mature offispring to- 

 gether on the trees. 



NATURAL ENEMIES. 



At least five species of insect parasites were found attacking the 

 black walnut curculio in its larva and pupa stages. Three species of 

 parasitic flies, determined by Dr. J. M. Aldrich as Chaetochlorops in- 

 quilma Coq., C'holomyia longipes Fab. (PL V, C), and Fannia canicu- 

 lar <s L., were reared from this host in considerable numbers. Two 

 hymenopterous parasites, determined by Mr. R. A. Cushman as Tri- 

 as pis curculionis var. rufus (Riley) and Thersiloclvus conotracheli 

 (Riley) (PL V, E) were also obtained in the rearing jars. Still 

 another parasite, determined by Mr. R. A. Fouts as a new species of 

 Belyta, was found in jars in which this curculio was being reared. 



THE HICKORY-NUT CURCULIO. 8 



The hickory-nut curculio is very similar to the two species just dis- 



'•■i. but it attacks the immature nuts of various kinds of hickory 



instead of walnuts. The beetles appear upon the trees somewhat later 



in spring than the other two and lay their first eggs in hickory nuts 



that are ;it least half grown, although before the nut kernels have 



begun to form. The most conspicuous manifestation of the presence 



he insed is the dropping of the infested nuts about midsummer. 



It i.-. not. linusual in .Inly and August to find in some localities (lie 



ground bcnc;it]i bearing hickory I rees strewn thickly with green nuts. 



imination of these nuts will disclose a brownish oviposition scar 



Bob, ; uborder Elbyncbopbora, family Curcullonldae, tribe 

 Cryptorbyncbinl. 



