526 Scientific Proceedings, Royal Dublin Society. 



never been seen actually placed on tlie stem or roots in the open field, but 

 in laboratory cages they have been found on the plant and on the roof of the 

 cage, as well as in the soil. This only occurred where the cage was so small 

 that the plant came in contact with the roof. The eggs are deposited in 

 clusters of three, four, five, or more ; but clusters of four appear to be most 

 prevalent. Those in a cluster are firmly pressed side by side, and are often 

 attached to a small lump of earth by means of a sticky substance at the 

 ends. 



A gravid female about to lay eggs descends from the feeding position on 

 the plant by means of the stem to the soil. In this she chooses a suitable 

 place in which to deposit a cluster of eggs, and this is usually somewhere 

 near the plant, in fine soil, and covered with a few small lumps of soil, which 

 serve as protection to the eggs. Tlierefore eggs are deposited in clusters just 

 below the surface of the soil, and in close proximity to a flax plant. It cannot 

 yet be definitely stated if oviposition occurs in flax-growing districts in soil 

 other than that in which flax seedlings are growing. Beyond the fact that 

 eggs were obtained over a period of one month, few data are as yet available 

 regarding the length of individual oviposition periods, or the number of eggs 

 deposited by each female. One female in captivity deposited thirty-seven 

 eggs in fourteen days, but then escaped. 



(c) Period of Incubation. — This, under the conditions which prevailed in 

 the field laboratory, which differed little from those in the open, extended 

 from fifteen to eighteen days. A record of the eggs deposited from the 16th 

 May until the 10th June gave incubation periods extending as above, the 

 mean of ten batches being 16'6 days. 



{d) Hatching. — A short time before the incubation period is complete 

 there is often seen a clear space towards one end of the egg, and at the same 

 time the outline of the larva can be traced, the head being particularly distinct. 

 From the nature of the rupture in the shell and its position, it is believed 

 that the larva when ready for emergence uses the mandibles in the process 

 of making the aperture through which it ultimately makes its exit. This 

 becomes more apparent when egg-shells from which larvae have hatched are 

 examined. Each has a similarly shaped aperture in a similar position, and 

 corresponding to that occupied by the larval head before emergence (PI. XV, 

 fig. 8). It is supposed that a rounded area is first gnawed by the mandibles, 

 and the rupture then completed by pressure of the thorax against that area, 



(e) Habits of neivly hatched Larvae. — These minute larvae are compara- 

 tively active, and are capable of crawling considerable distances. When 

 hatched on blotting paper in the presence of flax roots, they crawled about 

 slowly for some time, and ultimately went to a young portion of the root to 



