Cl{e Cnnnriian llntomolajbt. 



Vol. XLII. LONDON, MARCH, 1910. No. 3. 



NOTES ON LTXUS MARGINATUS SAY. 



BY MERRILL A. YOTHERS, E. LANSING, MICH. 



While collecting under a fence at the Michigan Agricultural College 

 on the 4th of September, 1909, I noticed a great many swellings, about as 

 large as peas, on the stems of the low, flat shore weed, Polygonum littorale. 

 Upon opening these, I found that they were galls, containing a snout 

 beetle or its larva or pupa. Many of the beetles had already emerged 

 from their galls, in which there was always a hole in the apex or anterior 

 end of the gall. 



Every beetle found was lying snugly in his or her nest, with head 

 toward the terminal end of the twig. 



A great many larvae and pupae were found. At least one twig was 

 found which contained a larva, a pupa, an adult, and the empty galls from 

 which adults had emerged. 



The galls were generally scattered along the stems of the larger, 

 healthier plants. Some were close to the base of the plants, and some 

 were only a couple of inches from the tips, but more were found 

 about half the distance between bases and tips. The galls near the tips 

 being necessarily small contained the very young larvae, while the larger 

 galls near the base contained the pupae, large larvae, and adult beetles. 



The beetles and galls were found only in the larger, healthier plants 

 growing in protected places. None could be found on plants in such 

 places as lanes, lawns and pastures, though luxuriant growths of the plant 

 were found in such places. 



At the time of first finding this insect (Sept. 4), I collected several 

 adults, a couple of larvae and a pupa. One of the larvae was nearly full- 

 grown, the other was not more than half-grown. Some of the beetles 

 were just matured, others were quite ready to emerge, as some had 

 already done. 



On October 6th I collected several more adults, larvae and pupae. On 

 this date I found some very small larvae, as well as other sizes. 



The life-history of this species is not entirely known, so far as I have 

 been able to learn. The eggs must be laid just beneath the bark of the 



