DETERMINING SEX OF MOTHS. 



E. J. Smith, Sherbom, Mass., writes: "In your directions for determining 

 the sex of lepidoptera you do not mention the frenulum. This is in some moths 

 a much surer way than any other except dissection. A few family of moths 

 do not have it, but nearly all do. It is always single in the male and composed 

 of from two to six or more bristles in the female. It is sometimes concealed so 

 that a little denuding is necessary. To do this I use a small paint brush about 

 one-sixteenth of an inch in diameter, the bristles of which have been cut off so 

 as to make a rather stiff and blunt end. With this I rub the under side of the 

 wings gently, close to the body, until the frenulum is exposed, and then with a 

 lens of moderate power it is easy to see whether there is more than one bristle." 



SUNSHINE AND EGG LAYING. 



Some species of lepidoptera will not oviposit without being in the sun- 

 shine. This is especially true of some of the butterflies. Remember this and 

 sometimes experiment by placing the butterfly over her foodplant in a net or 

 cage which is exposed to the rays of the sun. As a rule, however, lepidoptera 

 should not be exposed to the direct glare of the sun. 



ARTIFICIAL LIGHT AND EGG LAYING. 



The introduction of a gas or lamp light to an apartment in which a female 

 is ovipositing will, in most cases, stop the process, and I have found this to be 

 especially the case with Catocalas. There are species, however, which may be 

 induced to oviposit by being placed in the light. The plan of actually squeezing 

 out eggs from the body of a refractory female is recommended as a last resort 

 to induce her to commence laying. 



FERTILE AND INFERTILE EGGS. 



Dr. Knaggs says: "If an egg, from having been yellow or orange, change 

 color to any of the tints of pink, rose, or red; from having been of reddish color 

 to any hue of lavender, lilac, purple; from white, drab, or cream-color to any 

 shade of brown or lead-color; from green to red or lurish purplish; or if an egg 

 becomes black or uniformly darker, or if it gets symmetrically marked, spotted, 

 banded, or ringed, flatten or change form without shrivelling, the chances are 

 that it is fertile, and that the natural changes are going on in the enclosed larva; 

 but if, on the other hand, the egg should show transparency at one point and 

 opacity at another for any length of time, or should go over its proper time of 

 hatching, or should curl or collapse, it may almost certainly be considered either 

 that the egg is unfertilized or that the contents have perished; for though the 

 soft eggs of some species do shrivel to a certain extent, even though perfectly 

 impregnated, it is assuredly, as a rule, a bad omen. Of course the above tests 

 are inapplicable to eggs which have rigid, opaque, and colored shells, but even 

 here an adept will detect a difference between a fertile and infertile ovum. It 

 will, however, be best for the collector to keep his eggs until he is quite sure 

 about them one way or other; remembering that the ova of the same species 

 at one time may hatch in the autumn, and another may lie over until spring." 



WHEN EGGS HATCH TOO EARLY IN THE SPRING. 



Hibernating eggs frequently hatch in the early spring before the leaves of 

 their foodplant have appeared. In such cases the unopened buds of the plant 

 may be gathered and split, and may be successfully offered as food for the 

 young larvae. Care must be taken to renew the buds frequently, as they dry 

 very quickly. 



178 



