198 THE CANADIAN ENTOMOLOGIST. 



EDITORIAL SUMMARY. 



In the American Naturalist for September we find two very interesting 

 papers on Entomological subjects. The first by Prof. C. V. Riley, on 

 " Controlling Sex in Butterflies/' in which he shows, we think pretty 

 conclusively, by the results of a number of experiments which he has 

 instituted, that the theory advanced by Mrs. M. Treat in the March 

 number of the Naturalist, to the effect that the relative proportions in the 

 sexes of butterflies can be controlled by the quantity of food given, is 

 untenable. Mrs. Treat contended that by half starving a brood of larvae 

 you would obtain as a result either exclusively males or a very large pro- 

 portion of such, while by liberal feeding the reverse would be the case, 

 the gentler sex greatly preponderating. Prof. Riley thus sums up his 

 results : " On the whole, if these experiments indicate anything, they 

 indicate that where more males than females are obtained from stinted 

 larvae, it is attributable to the fact that the females, being largest and 

 requiring most nourishment, succumb most readily under such treatment ; 

 rather than that the sexual characteristics are modified and determined by 

 such treatment." 



The second paper is the " Third Annual Report on the Injurious and 

 Beneficial Insects of Massachusetts," by A. S. Packard, Jr. 



The author states that at a low estimate there are probably upwards of 

 50,000 species of insects in the United States, the proportions in the 

 different families being roughly estimated as follows : — Hymenoptera 

 (bees, wasps, ichneumon flies, sawflies, &c.,) 10,000; Lepidoptera (but- 

 terflies and moths,) 5,000 ; Diptera (two-winged flies,) 10,000; Coleoptera 

 (beetles,) 10,000 ; Hemiptera (bugs, &c.,) 10,000, with several thousand 

 species of Orthoptera (grasshoppers, &c.,) and Neuroptera (dragon flies, 

 caddis flies, &c.) A large number of these insects are as yet undescribed, 

 so that in the mere determination, classification and arrangement of these 

 vast hosts of animated creatures, an immense task has to be performed 

 for which the present number of working Entomologists is entirely insuffi- 

 cient, there being, the author states, but about thirty in this country who 

 publish anything relating to insects. Hence the more important work of 

 studying the history and habits of the various species is necessarily very 

 much interfered with. 



