NOTES ON THE LIFE-HISTORY OF OCNOGYNA BOETICA. 



237 



sixty miles. I was glad to get even this small glimpse of one of the 

 most interesting islands of the world, and live in hopes of some day 

 visitine- it. 



Notes on the Life=history of Ocnogyna boetica {in'th plate). 



By H. POWELL. 



On November 17th, 1904, I received from Dr. T. A. Chapman a 

 good-sized batch of the ova of this interesting Arctiid species. Being 

 very busy at the time, I was unable to critically examine the eggs, but 

 made a superficial examination which resulted in the following notes : 



Egg. — Small, round, shiny, of a butter-yellow colour ; the batch 

 contained a considerable number, but it was not possible to determine 

 how many, for they were all attached together in an elongated lump, 

 those occupying the interior of the mass being hidden. Dr. Chapman 

 has observed that the $ moth chooses as moist a place as possible for 

 laying her eggs, and added, " The ? , I imagine, almost burrows into a 

 hole to find a place to lay them where they may be damp enough." He 

 was afraid that he had kept them too dry and that they had thereby been 

 damaged. However, this was not the case. I kept them in a tin box 

 in a room facing south, where there was a fire at night. Very cold 

 weather set in at the end of November, night temperatures of — 4°C. and 

 even— o°C., but as they were not exposed to it they did not suffer. 

 On November 281;h, the ova began to darken, and by December 1st the 

 whole mass, with a few exceptions, had turned graphite-gray. During 

 the time I had them, I kept a bit of lettuce leaf (changed from time to 

 time) in the tin box with them in order to provide moisture. The 

 earliest larv« emerged on December 2nd, almost all the rest on 

 December 3rd and 4th. 



FooDPLANis. — I tried the young larvae with several foodplants, 

 including Calycotowe spinom which they would not touch. It was the 

 nearest approach I could get to broom [SpartiiiuijunceuDi) which Dr. 

 Chapman says is their normal foodplant. The broom has not, at this 

 time, a trace of a leaf on it, and I examined many bushes for a leaf in 

 vain. The larvae picked out lettuce and groundsel as their foods, 

 though one or two ate some Tara.racinii. As they do well on groundsel, 

 I planted a big pot of it, intending to turn them out on it. A large 

 number of the young larvae died without attempting to eat anything, 

 and a number of eggs, although the larva; developed in them, did not 

 hatch, mostly I think because they were in the centre of the mass and 

 the young larvae could not free themselves. The larvae look something 

 like those of young Arctia rillica, but are not so hairy. They are not 

 very lively. A few larvae appeared in the second skin on December 

 14th, several more on December 15th. 



Larva. — First imtar : Length of young larva l-5mm. to l-6mm. 

 Head, black and highly polished. It has some long black hairs, and 

 shorter ones, round the mouth, but none so long as those from the 

 body tubercles. The body colour is light grey, pale straw-grey as the 

 larva grows and shows more of it. It is semitransparent and shows a 

 glow through when the light is thrown up from the reflector. The 

 dark appearance of the larva when quite young is caused by the large 

 jet-black tubercles set near together, with their long black hairs, 

 leaving but little of the skin to be seen. As the larva fills out, the 



