434 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 5 



NOTES ON LIXUS CONCAVUS 



By Harry B. Weiss, New Brunsivick, N. J. 



This beetle commonly known as the rhubarb curculio emerges from 

 its winter quarters about the last week of May in the latitude of New 

 Brunswick. It hibernates, presumably under debris commonly found 

 in the field, inasmuch as two specimens were taken last December 

 from under dead leaves and rubbish and one from under a loose piece 

 of bark at the base of a stump. Careful searches at different times 

 later in the winter resulted in none being found. 



Egg deposition commences soon after emergence, as eggs were col- 

 lected in the field on the first of June in the stems of Rumex crispus, 

 which is undoubtedly the favorite food plant of the larvse. Sun- 

 flower and thistle were examined for egg punctures with negative 

 results and in one instance only, eggs were found in a species of poly- 

 gonum or smartweed. 



In dock the egg punctures occur from the base of the stem all the 

 way to the tip of the plant and it is not uncommon to find from fif- 

 teen to twenty punctures in a stem three feet high. Occasionally 

 they occur in the leaf petiole. Not all of these punctures, however, 

 contain eggs, only a comparatively few. Upon cutting into some 

 stems, many egg cavities were found to be empty and the surround- 

 ing tissue showed no evidence of larval activity. Other stems showed 

 many empty egg cavities together with channels eaten by the first 

 hatched larvse; Sometimes these channels cut through egg cavities 

 and other times cleared them. In either case more egg cavities were 

 empty than should have been the case, especially as only one or two 

 larvse were usually found. From this one is forced to conclude that 

 the beetles are either often disturbed during oviposition and get no 

 further than the cutting of the cavity, or that the first larvse which 

 hatch out eat any eggs they may come across on their way to the root. 

 No matter how many egg punctures are in a stem, not more than two 

 or three larvse can be found early in the season and later not more 

 than one. 



In the laboratory, eggs hatched in from seven to nine days during 

 June and in the field egg laying continued up until July 20, after which 

 no eggs were found. Egg deposition, however, is practically over by 

 the middle of June as on June 19 one egg was found to eighteen larvse. 



The newly hatched larva first eats out a little chamber about a quar- 

 ter of an inch or less above the egg cavity. This is really an enlarge- 

 ment of the egg cavity. It then goes down through the stem, cutting 

 a more or less irregular channel, until the root is reached, where it 



