l8o ENTOMOLOGICAL NEWS. [April, 'l6 



The Biota of Nantucket. 



For a number of years past Mr. Eugene P. Bicknell has been publish- 

 ing in the Bulletin of the Torrey Botanical Club a series of papers on 

 the vascular plants of Nantucket, in which he has brought out a num- 

 ber of very interesting facts. Intensive study has not only yielded 

 much of interest in connection with distribution, but has brought to 

 light a number of new species, belonging to such genera as Amelan- 

 chicr. Ilex, etc., conspicuous members of any Flora. It can hardly be 

 doubted that a similar study of the animals, and particularly the in- 

 sects, would yield like results. Sorting over some material which 1 

 collected on Nantucket several years ago, I found some species which 

 it may be worth while to record. 



Hymenoptera (bees) : Halictus capitosus Smith, $ , smaller than 

 usual ; H. pilosus Smith, $ . 



Neuroptera: Chrysopa harrisi Fitch, det. Banks. 



Araneina (Spiders, all very kindly determined by Air. N. Banks): 

 Epcira pratensis Hentz, E. trivittata Keys., Zilla atrica Koch, Plectana 

 stcUata Hentz, Theridium frondciim Hentz, Ceratinella emertoni Cam- 

 bridge, Agelcna naez'ia Walck., Chibiona sp., juv., Xysticus triguttalus 

 Keys., Phidippus podagrosus Hentz. — T. D. A. Cockerell, Boulder, 



Colorado. 



The Cactus-feeding Volucellines (Dip.), 



South Coronado Island (Lower California) is extensively overgrown 

 with cactus, apparently Opuntia Uttoralis. When my wife and I visited 

 the island on Aug. 21, we found what appeared to be a single variable 

 species of Volucelline fly very abundant. Several were collected, and 

 on examination prove to represent two genera and species, namely 

 Volucella aznda O. S. and Copestylum nuirginatiim Say. At Boulder, 

 Colorado, July 19, I collected a superficially similar insect (more like 

 the Copestylum than V. avida) at flowers of Helianthus annuiis; this is 

 Volucella fasciata Mcq., a variety with dark reddish antennae. On 

 looking up the literature, I find that all these three insects feed in the 

 larval state on cacti. They form a peculiar group, and in all respects 

 appear to be closely related, except for the extraordinary antennae of 

 Copestylum. The latter genus surely evolved from Volucella, but who 

 can say how the change came about, or what purpose it serves? There 

 was, so far as we know, no change in habits. One is reminded of cer- 

 tain strange modifications of the antennse of chrysomelid beetles, pro- 

 duced by Professor Tower under experimental conditions at Chicago, 

 and wholly without functional significance, so far as we can learn. One 

 of the females of V. avida from S. Coronado is quite small, no larger 

 than V. fasciata. 



The Atriplex bushes on S. Coronado carried many galls, doubtless 

 belonging to Asphondylia atriplicis Twns., as no difference was appar- 

 ent. — T. D. A. CocKERELL, Boulder, Colorado. 



