Sept., 1911.] Wheeler: Notes on Beetles of Genus Xenodusa. 167 



According to Wasmann'" " the species of Xenodusa, in the shape 

 of the labium, are intermediate between Atcmclcs and Lomcchiisa. 

 In other respects also the nearctic genus Xenodusa coimccts, so to 

 speak, the two old world genera, in so far namely, as some of the 

 species (especially X. caseyi) resemble Atenieles in thoracic struc- 

 ture, while others (X. sharpi) are more like Lomeehusa." He adds, 

 however, that notwithstanding these intermediate characters, " we 

 are unable to regard Xenodusa as a connecting link between Atenieles 

 and Lomeehusa, since the much elongated shape of the antennae and 

 legs indicates a peculiar direction of development, which is not observ- 

 able in the two old world genera and is probably to be interpreted 

 as an adaptation to the relatively very large hosts of Xenodusa (Cani- 

 ponotus, Formica)." The larval characters above described certainlv 

 seem to confirm Wasmann's view of the peculiar and independent 

 developmental trend of the genus Xenodusa. and the long legs and 

 antennae of the adult beetle are. indeed, in all probability, an adapta- 

 tion to its hosts, since these organs are verv long in the Camponoti 

 with which it passes the winter and in F. incerta. which, like the 

 other forms of the paUide-fuli'a group, has much more slender legs 

 and antennae than anv of our other Formiecr. The great length of the 

 appendages in the larva must be directly correlated with their un- 

 usual length in the imaginal beetles. 



The recorded winter hosts of A', eaz'a are C. hereuleauus subsp. 

 pennsylvanicus and C. ligiiiperda var. no-c'cboraeensis. To these must 

 be added C. penusylz'aiiiciis var. ferrugiiieus. as Dr. A. Fenyes has 

 shown me one specimen of the beetle taken in a nest of this ant at 

 Bloomington, Indiana. Still another host has been recently dis- 

 covered by Messrs. W. Reiff and E. H. Strickland, April 19, 191 1. 

 These young men found a couple of the beetles in two colonies of 

 C. castaneus subsp. americanus at Norwood, Mass. This being a 

 ground-inhabiting Caniponotus, would seem to be a more natural 

 winter host than the various wood-inhabiting forms of C. hereuleauus 

 with which it has always been taken heretofore. 



On May 6, 191 1, I took a specimen of X. cava resting on a stump 

 near the top of (jreat Blue Hills, near Boston, Mass. As there 

 was no Caniponotus colony in the stump, nor within several yards of 



'" Zur Biologic und Morphologic der Lomcchusa-Gruppe. Zool. Anzeig.. 

 1897, pp. 463-471- 



