Dec, '05] ENTOMOLOGICAL NEWS. 335 



food to the pierides of the region, which perhaps do the tree a service in 

 aiding its pollinization. But what is the cause of these immense 

 flights — of these enormous assemblages that move in masses along the 

 rivers? M. Goeldi does not attempt to explain them. Spruce thought 

 that the flights were mostly of males and on the other hand that the 

 migratory instinct of the females was to be explained by the necessity 

 of seeking certain species of mimosas to lay their eggs thereon. But so 

 far as we know, no one has advanced any satisfactory explanation of the 

 reason why myriads of pierides should thus join in a common flight." — 

 Translation vtade/orTuK Liter arv Digest. 



New Haven, Ct., Aug. 4, 1905. 

 ■ Dear News. — I trust that you will allow me space in your columns to 

 call attention to a few good and bad features in the mechanical " make- 

 up" or form of insect catalogues, check lists and monographs. Cata- 

 logues and lists are used not only by the specialist, but also by the general 

 worker and amateur. Curators of collections, perhaps, are obliged to 

 use them as often as anyone, and it is in their behalf that I would speak. 

 I have just been examining Prof. J. M. Aldrich's Catalogue of North 

 American Diptera, and have noted its many admirable features. The 

 specific name in heavy faced type at the left margin of the page, with the 

 references indented, is a convenient arrangement, and is found in Dyar's 

 List of Lepidoptera, though in the latter numbers precede the specific 

 names. The numbers are omitted from Aldrich's list, but except for 

 those who exchange and write about species in numerical terms this is 

 hardly an inconvenience, as the species are arranged alphabetically under 

 each genus. The references, where each author's name begins a sepa- 

 rate line, are certainly more convenient than when arranged as in Dyar's 

 list, though not so economical of space. Localities printed on the right 

 margin of the page, as in Dyar's list, certainly facilitates looking up the 

 distribution of a species, and must be considered a good feature. 



But one of the chief disadvantages of both books just mentioned is that 

 the running titles at the tops of the pages give no idea of the contents of 

 the pages under them, but are the titles of the book. Not so with Osten 

 Sacken's catalogue, where only the name of the family appears at the top 

 of each page. 



From the usual arrangement, where the name of the institution or the 

 title of the book is continued as a running title throughout the work, we 

 find the other extreme in Mrs. Fernald's list of Coccidae, where running 

 titles are omitted altogether. Smith's Insects of New Jersey would be 

 far more convenient for ready reference if the right-hand page gave as a 

 running title the name of the order, if not the family, treated on that page. 

 It is probably unnecessary that such a title be printed on both pages, and 

 the ideal arrangement seems to be that found in the following works : Wil- 

 liston's North American Diptera ; Saussure's American wasps ; Cresson's 

 North American Hymenoptera ; Hagen's North American Neuroptera, 

 and Leconte and Horn's Classification of North American Coleoptera. 



