LIFE-HISTOKY OF AGROTIS AGATHINA. 169 



"A curious result happened with some spring-laid iUnstrarid (ictrtilmiarid) 

 eggs, iced before they had turned red ; two of them Ijccame l)lackish 

 while in the ice (where the eggs were kept for 17 days), and hatched 

 the day they were taken out of the ice, or the next day, the rest 

 remaining red for several days, and hatching in from 11 to 13 days 

 after removal from the ice. These are strong examples of individual 

 character manifested at a very early age." This would, indeed, be so, 

 but it is remarkable that two eggs of a batch should exhilnt such a 

 decided difference from the remainder. 



With regard to high temperatures, ]\Ir. Merriiield reports that the 

 eggs of these two species seemed in all cases uninjured by a tem])erature 

 of 80° to 90'^, their development being on the contrary accelerated by it. 



14. On the fertilization of the ovum. — The eggs are developed 

 in the ovaries of the parent, whence they jmss down the oviduct into 

 the vagina. In connection with the vagina are one or more })ouches 

 called receptacnla seminis, in which the semen is stored after coiiulation ; 

 from these it passes into the vagina as the egg passes along it to the 

 ovipositor, and sperm-cells enter the egg through the micropylar tubes, 

 one of which fertilizes the egg, so that fertilization of the egg takes 

 place at the time it is being laid, by the spermatozoa passing througli 

 the microp3'lar pores as the egg leaves the opening of the receptacnla 

 seminis. It is sometimes noticed that the latest-laid eggs of a batch 

 are infertile ; this is probably due to the supply of sperm-cells being 

 exhausted before all the eggs are laid. Mr. Bacot, however {Ent. 

 Record, vol. v.) records a case where only eight eggs of E. fetralunaria 

 out of a batch of 146 proved fertile, and these were laid about half- 

 way through the batch. In some insects the sperm fluid retains its 

 fertilising properties for a very long time. For exam])le, the queen 

 bee and ant pair but once, yet they continue to lay fertile eggs for 

 years. In lepidoptera the sperm can only last from autumn until the 

 following spring, and then only in such species as copulate before 

 hybernation. Usually, of course, it lasts a much shorter time. 



£ contribution to tlie l(noWledgc of tlie Earlier stages in tlie 

 Life-piistopy of Hgrotis agathina. 



By W. S. RIDING, M.D., F. E.S. 



On August 26th, 1893, several A. agathina were taken on the 

 heather at Gittisham by my son. One ? was kept for eggs. She 

 began scattering these on the stems and leaves of the heather on the 

 29th, and laid, during the following week, close upon 100. By Sept. 

 15th some, previously of a dirty-white colour, had become mottled 

 with purj)le and, in a few days more, many were leaden-coloured and 

 the young larvae were ready to emerge. A few broke their shells on 

 the 22nd. The eggs are nearly s})herical, slightly flattened at the base 

 of attachment and somewhat less so at the apex, about -875 mm. in 

 diameter, with 26 to 32 rather prominent ribs, each alternate one 

 reaching nearer to the apex which is reticulated round the micro})yle. 

 There are faint transverse striations. The young larvic emerge at the 

 side of the apex and do not eat the shell. The body is bluish-leaden in 

 colour and scattered all over with a few short hairs; the head is l»rown 



