114 THE ENT03I0L.0CUST's KE(JOKl). 



shrivelled iq) and died shortly afterwards. The fuliginosa both spun up, 

 after waiting for a week or more to see if spring had really come. Of 

 the two rnhi which pupated, the smaller, Avhich turned out to be a male, 

 emerged under ten days from becoming a pupa ; the larger one pro- 

 duced a fine female about three days later, so tliat the transformation 

 from the hibernating larvae to the perfect insect took only three weeks 

 in the case of the female, and even a shorter time with tlie male. The 

 ftditjinosa also took but three weeks or a little longer, perhaps, to com- 

 plete their life history. These, with the female rubi, were of normal 

 size and colouring, but the male was rather small and light. I was much 

 delighted with my success, and repeated my experiments witli ten or a 

 dozen larvfv, and with much the same result. From the Monday in 

 Christmas Aveek till the time that I left liome again — al tout January 19th 

 — we had an almost continuous frost, and sometimes very severe, the 

 thermometer once registering only live degrees above zei'o in our garden. 

 I pur})osely left the rest of my larvte exposed for a fortnight to this 

 severe weather, till the sods and tlie soil beloAv were frozen as liard as 

 bricks for several inches. I tlien carried several of the sods l)odily into 

 the gTeenhouse to tear up, and tin-ned out many fat caterpillars covered 

 with hoar frost, some of Avhieh I liad to be very careful not to damage, as 

 they were very securely frozen into the soil. As it was, one specimen oi 

 fulujinosa left all the hair of one side behind, but in the end it seemed to 

 be no worse, and arrived at the moth stage in due course. One peculiar 

 incident I should like to mention witli regard to the A\-ay in which tlie 

 frost had affected some of the " foxes." In searching, I picked out one 

 or two Avhich were stretched out and a|)parently dead. I took one and 

 tried to break it in two, but altlK)ugh it cracked inside as tliough it were 

 full of frozen snow, the skin was tough and would not break. I 

 then, with the idea of melting the inside, and never for one moment 

 dreaming that there was any life left in the larva, laid it on one of the 

 hot pipes. Shortly afterwards I sarw it moving. I huniedly took it off, 

 and although it continued alive for some time, the trial liad been too 

 severe for it. The others that were in the same crystallized condition 

 I placed in the box of warm moss, and they recovered quite satisfac- 

 torily, like their curled-up companions. Why some and not others should 

 liave assumed this curious state is more than I can understand, but I 

 think that iew people would have hesitated in saying that these 

 stiffened forms were dead. Following the same plan as hei'ctofore, I 

 succeeded in getting more than fifty into pu});e, a few uuly dying. The 

 rest of the larv;e I have still left in the cucumber frame, to see if they 

 will naturally turn later in the spring. Those wliich I got to the pupa 

 state varied consideraljly in size, and, on the whole, were smaller than 

 usual. Aljout twenty emerged while I was at home ; the rest, whicli 

 I was stupid enougli to take out of their warm climate, and bring back to 

 Cambridge, all died except two. The fidujinosa were not affected in the 

 same way, and all came out, although I had no means of keeping them 

 in a warmer temperature than my room. A curious point as to the sex 

 of rnbi, is that by far the greater number of pupa' produced females, 

 which I have always regarded as the rarer of the tAvo. Most of tlie 

 specimens are certainly under the normal size and of lighter colouring. 

 It will be seen, then, by the foregoing, that I have subjected these tAvo 

 regularly hibernating larvae to severe tests. They have been taken in the 

 frozen state at aboiit 21j" Fahrenheit, or less, and suddenly raised to 



