216 Lilian J. Gould's experiments 



During the whole period of experiment all the larvae 

 were kept in numbered glass cylinders, supported on 

 jdates over vessels of water, like those used by Mr. 

 Poulton in previous experiments. A hole through the 

 plate allowed the stems of the food-plant to reach the 

 water, and thus it was kept fresh. The tops of all 

 cylinders were covered with fine white muslin, held in 

 j)lace by elastic bands ; and to prevent the escape of 

 larvie, when very small, l)etween the cylinder and the 

 plate, the junction was surrounded by very line sand. 



Section I. 

 Notes on larvae of Rumia crataegata. 



On June 23rd, 1890, I received, from Mr. Poulton, 

 fertile ova of 11. cratcegata, from one parent, for purposes 

 of experiment. 



June 24th. — 22 larvae hatched. These were all placed 

 in one cylinder, and fed on hawthorn, the sprigs of the 

 food-plant not being chosen at this time with any regard 

 to colour. The larvae were examined several times daily, 

 and days on which no alteration in their condition was 

 observable were noted as "no change"; these are 

 omitted in the present account. 



July 1st. — The first ecdysis occurred ; all the larva) 

 having hatched out on the same da}', moulted at the 

 same time, with only a difference of hours. 



July 7tli. — I divided the larva3 into two sets, placing 

 11 in cylinder 9, and 11 in cylinder 5. The following 

 observations refer to those in cylinder 9, which were 

 supplied from this time with green leaves only, very 

 young shoots of hawthorn being selected for this pur- 

 pose. My intention was to exclude every colour but 

 green from their surroundings, but this was rather 

 difficult, as the stalks of the leaves of hawthorn were 

 too short to admit of their being gathered and kept fresh 

 in water separated from the twig, and the stems were 

 always liable to be brown or brownish in colour. This 

 difficulty was obviated as far as possible by selecting 

 only the very youngest shoots of hawthorn, in which the 

 leaves were very bright green, and one side of the stem 

 was always bright green, the other side of the stem 

 and the thorns being of a crimson colour. 



July 9th. — The second ecdysis occurred. From this 



