182 ENTOMOLOGICAL SOCIETY 



NOTE ON THE FOOD-HABITS OF SOME HALTICIDS. 



BY E. A. SCHWARZ. 



The North American Halticini were not monographed until 

 the year 1889, when Dr. Horn published his excellent "Syn 

 opsis of the Halticini of Boreal America." Prior to that date 

 we had, in the more intricate genera, only isolated descriptions 

 from which an accurate determination was, in most instances, 

 not possible, the result being that not only our collections were 

 full of wrong determinations or undetermined specimens, but 

 that such erroneous determinations were also published in 

 faunal lists or records of food-habits. Since many Halticids 

 are of greater or smaller economic importance, it is certainly 

 desirable to know whether or not the published records of 

 food-habit, life-history, etc., are reliable, i. e., based upon cor 

 rect determination of species. I have thought it worth while 

 to briefly review those of the more important records to which 

 I have access in my private library. In the absence of typical 

 specimens I am, of course, unable, in most instances, to correct 

 the records, and my only object is to point out where, in my 

 opinion, the determinations are open to doubt and to recom 

 mend that such doubtful records should not be used in future 

 unless they be verified by renewed observation or by examin 

 ation of the typical specimens. Those species, the records of 

 which appear to be based on correct determination, are not 

 mentioned in the following notes. 



In speaking of the food-plants of Halticids (and of many 

 other phytophagous Coleoptera) we must discriminate between 

 the food-plants of the larva and those of the imago. In many 

 species the imagos feed, often in vast number of specimens, on 

 a variety of plants which are not the food-plants of the larva, 

 and it may be said that, as a rule, the imagos are by far more 

 polyphagous than the larvae. The true food-plant of a species 

 is, of course, that upon which the larva feeds. Some observers 

 have failed to make this discrimination and give, in many in 

 stances, a certain plant as the food-plant of a species whereas, 

 in reality, they mention only one of the food-plants of the 

 imago. 



Disonycha pennsylvanica and quinquevittata and their varie 

 ties were formerly often confounded, the large and pale varieties 

 of the former species, with feeble or obsolete elytral sulci, being 

 more especially the cause of confusion. Thus the records of 

 the food-habits of the two species are by no means reliable. 

 The larva of D. pennsylvanica undoubtedly feeds on various 

 species of Polygonum and Rumex, and the imagos occur and 

 feed also on Salix, but whether the larva also feeds on the 

 latter plant is still somewhat doubtful. Mr. Bruner states 



