164 THE CANADIAN ENTOMOLOGIST. 



Here is a broad field. From the special range of my own studies let me 

 recommend to any one eager for this work to choose the eggs of our com- 

 mon copper butterfly, which she will lay to order on sorrel, and the earlier 

 stages of which can be obtained from the parent at two or three different 

 times of the year ; or the eggs of any of our common skippers, which 

 deposit on grass, and which are equally easy to obtain, although only once 

 a year. Or, if we turn to Orthoptera, the eggs of our common Oecanthus, 

 concealed all winter in raspberry twigs, are more transparent and more 

 easily obtained than those of any other cricket ; and our knowledge of the 

 embryology of any of the Gryllidcce is very fragmentary, and of this partic- 

 ular tribe, nil. Better still, perhaps, would be the choice of our common 

 walking-stick, as it belongs to a bizarre and isolated type, now known to 

 be of very ancient ancestry, and of whose embryonic history nothing has 

 been published. I have, indeed, a few incomplete notes upon this insect, 

 but they relate wholly to a late period of development, and were made 

 before the time of the microtome, when work over such coarse-shelled 

 eggs was very difficult and unsatisfactory. The eggs may be readily 

 procured, the insect being abundant in scrub-oak fields ; the mother drops 

 the eggs loosely on the ground, and from imprisoned specimens I have 

 procured scores in a single season. Any one who will glance over the 

 history of what has been done in insect embryology will be able to select 

 a hundred examples as important and as easy to obtain as those already 

 named, and by concentrating his work upon them will do better service 

 than in an aimless selection of what may come to his hand. 



In following the postembryonal history of insects there is work for all. 

 While allied forms have in general a very similar development, there are 

 so many which are unexpectedly found to differ from one another, that 

 every addition to our. knowledge of the life histories of insects is a gain, 

 and they are to be praised who give their close attention to this matter. 

 Here is a field any entomologist, even the most unskilled, may cultivate 

 to his advantage and with the assurance that every new history he works 

 out is a distinct addition to the science. The importance of an accumu- 

 lation of facts in this field can hardly be overestimated, and those whose 

 opportunities for field work are good, should especially take this sugges- 

 tion to heart. Nor, by any means, is the work confined to the mere 

 collection of facts. How to account for this extraordinary diversity of life 

 and habits among insects, and what its meaning may be, is one of the 

 problems of the evolutionist. There are also here some especially curious 



